Three Letter Plurals

Note: These lists exclude words containing heavy letters, as well as words considered to be very common

Hooks Which can be Pluralised with (E)S

AAL	an Indian shrub		
ABA	an outer garment worn by Arab women
ABB	a textile yarn
ABO	an aboriginal
AGA	a Turkish commander
AIA	an Indian nurse-maid
AIN	a Hebrew letter
AIT	a small island
ALA	an outgrowth on a fruit
ALB	a priest's long, white vestment
ALP	a mountain
ALT	a high tone
AMA	a maid (also AMAH)
AMI	a friend (Fr.)
AMP	short for am pere or amplifier
AMU	a unit of mass
ANA	in equal quantities (in recipes0
ANE	Scots for one
ANI	a tropical American bird
ANN	a payment to a parish minister's widow
ARB	a short form of arbitrageur, a stocks and shares shyster
ARD	a primitive plough
ARF	a barking sound
AWL	a pointed toil for boring
AYU	a small edible Japanese fish

BAC     university degree of bachelor
BAL	a balmoral shrub
BAP	a large, flat breakfast roll
BEL	a measure of noise
BEN	a mountain
BEY	a Turkish governor
BIO	a short form of biography
BOD	a person
BOH	an exclamation used to startle someone
BOK	a goat or antelope
BOR	East Anglian form of address meaning neighbour

CAY	a low islet
CEE	the letter 'C'
CEL	a short form of celluloid
CEP	a kind of edible mushroom
CHA	tea
CHI	feminine of chal, a fellow or person (also KHI)
CID	a chief, captain or hero
CIT	contemptuous term for one who is not a gentleman
COR	a Hebrew measure
COS+	a crisp,, long-leaved lettuce

DAH	same as DA (a Burmese knife)
DAK	in India, the mail or post
DAL	a kind of Indian edible pea
DAN	a level of efficiency in Japanese combative sports
DEB	colloq. form of debutante
DEL	a mathematical symbol
DEV	a hindu god (also DEVA)
DEY	formerly, the pasha of Algiers
DIV	an evil spirit of Persian mythology
DOC	contraction of doctor
DOH	a musical note
DOL	a unit of pain intensity
DOM	a title given to certain monks
DOO	Scots word for dove or pigeon
DSO	same as ZO, DZO, ZHO, DZHO (a Himalayan  ox)

EAU	water (Fr.)
EDH	a letter used in old English (also ETH) 
EFT	a newt
ELD	old word for age or old age
ELL	a measure of length
ELT	a young sow
EME	obs. word for uncle
EMF	electromotive force
ENE	poetic for even
ENG	a phonetic symbol
ERG	a unit of work
ERK	a slang word for aircraftsman
ESS+	same as ES (the letter 'S')
EST	a programme designed to develop human potential
ETA	a letter of the Greek alphabet 
ETH	same as EDH, above

FAH	same as FA (a musical note)
FAW	a gypsy
FEH	a pe, or peh (a Hebrew coin)
FEM	a passive homosexual
FID	a conical pin of hard wood	
FOH	an interjection expressing disgust or contempt (also PHO)
FOU	a bushel
FOY	allegiance, loyalty
FUM	a fabulous Chinese bird (also FUNG)

GAL	a girl
GAT	a pistol
GED	a food fish
GEN	general information
GHI	clarified butter (also GHEE)
GID	a sheep disease
GIO	a gully or creek (also GOE, GEO)
GIT	a stupid person
GNU	an African antelope
GOA	a Tibetan gazelle
GOE	same as GIO, above 
GON	a geometrical grade
GOO	a sticky substance
GOV	short form of governor (also GUV)
GOY	a Gentile
GUB	a white man
GUE	same as GU (a violin formerly used in Shetland)
GUL	a design in oriental carpets
GUP	gossip, prattle
GUR	an unrefined, sweet cane sugar
GUV	same as GUV, above

HAH  	a sound of surprise
HEH	a Hebrew letter	
HEP	a rosehip
HET	slang word for heterosexual
HIN	a Hebrew liquid measure
HON	short for honey, as a term of endearment
HUN	a barbarous and destructive person

IDE	a type of fish
ION	an electrically charged particle
ISH+	legal word meaning issue or expiry
ISM	any distinctive theory or fad
ISO	short for isolated replay, a TV and film facility
ITA	the miriti palm

KAB	an ancient Hebrew unit of measure
KAF	a Hebrew letter (also KAPH)
KAI	in New Zealand, a meal
KAT	same as QAT, KHAT (an East African shrub)
KAY	the letter 'K'
KEA	a large New Zealand parrot
KED	a wingless fly that infests sheep
KEF	a drug that produces a dreamy repose (also KIF)
KET	Scots word for carrion, rotting flesh
KHI	same as CHI, above
KIF	same as KEF, above
KOA	a Hawaiian acacia
KOB	an African waterbuck
KOP	a South African word for hill
KOR	a Hebrew unit of measure
KOS+	an Indian measure of distance (also COSS)
KOW	a bunch of twigs
KYU	a novice grade in judo

LAB	a short form of laboratory
LAC	a dark-red resin
LAH	same as LA (a musical note)
LAR	the god relating top a house
LAT	short form of latrine
LAV	short form of lavatory
LEA	a meadow or pasture
LES+	same as LEZ (short form of lesbian)
LOD     a statistic relating to the odds of an event
LOY	a long, narrow spade
LUM	a chimney (Scots)
LUR	a Bronze Age trumpet
LYE	a short branch of a railway

MAC	a short form of mackintosh
MAE	more
MAK	same as make
MAL	pain, sickness (Fr.)
MAM	dial. for mother
MEG	a halfpenny
MEL	honey
MEM	a Hebrew letter
MEU	the spignel plant
MHO	a unit of electrical inductance
MIB	a type of playing marble (also MIG)
MIG	same as MIB, above
MIL	a unit of wire measurement
MIR	a Muslim ruler
MNA	a Greek unit of weight or money (also MINA)
MOA	a gigantic extinct bird
MOC	a moccasin
MOD	a Highland Gaelic festival
MOE	a wry face
MOL	a mole
MOM	Amer. colloq. for mother
MON	a Japanese family badge or crest
MOR	a layer of humus
MOT	a word (Fr.)
MOU	a mouth (Scots)
MOY	a coin or a measure
MUN	dial. for man
MUT	alternative spelling of mutt

NAM	distraint (also NAAM)
NAN	slightly leavened bread (also NAAN)
NAT	colloq. form of nationalism
NAY	a denial
NED	a young hooligan
NEF	a church nave
NEK	a col, a pass in a mountain range (S. Afr.)
NEP	dial. for catmint, a plant attractive to cats
NID	a pheasant's nest or brood
NIT	a young louse; a fool
NOB	a person of high social rank
NOM	name (Fr.)
NUR	a knot on a tree (also KNUR)

OBA	in West Africa, a chief or ruler
OBE	a form of sorcery of African origin
OBO	a vessel for carrying oil and bulk ore
ODA	a room in a harem
OHM	a unit of electrical resistance
OHO	an expression of triumph or surprise
OIK	an inferior person
OKA	a Turkish unit of weight
OOF	slang word for money
OOM	uncle (S. Afr.)
OON	Scots for oven
OOT	an out
ORC	a killer whale (also ORCA)
ORD	a point of a weapon
ORF	a viral infection of sheep
ORT	a leftover from a meal
OSE	an esker, a narrow ridge of gravel and sand
OUD	a stringed instrument of Northern Africa
OUK	Scots for week
OWT	dial. for anything
OYE	same as OE, OY (a grandchild)

PAC	a shoe patterned after a moccasin
PAH	same as PA (a Maori port or settlement)
PAM	the knave of clubs
PEC	colloq. shortening of pectoral muscle
PED	a shortening of pedestrian
PEH	same as PE (a Hebrew letter)
PHI	a letter of the Greek alphabet
PHO	same as FOH, above
PIA	a tropical plant
PIC	colloq. for picture
PIR	a Muslim title of honour, given to a holy man
POA	a meadow-grass plant
POI	a Hawaiian dish of fermented taro
POL	a politician
POM	colloq. for Pomeranian dog
POW	head (Scots)
PSI	a letter of the Greek alphabet
PUS+	thick yellowish bodily fluid
PYA	a copper coin of Burma

RAI	a modern North African form of popular music
RAS+	an Ethiopian prince
REB	a Confederate soldier
REC	a recreation ground
REE	an enclosure for sheep (Scots)
REG	a regulation
REH  	an accumulation of salts on soil
REI	a Portugeuse coin
REM	a unit of radiation dosage
RES+	a short form of reservation
REW	Spens. spelling of row
RHO	a letter of the Greek alphabet
ROE	a mass of fish eggs (adj. ROED)
ROM	a gypsy man
ROO	a short form of kangaroo
RYA	a type of Scandinavian rug

SAI	the capuchin monkey
SAL	a large North Indian tree
SAN	a Japanese form of address
SEL	Scots form of self
SEN	a Japanese monetary unit
SER	a unit of weight in India
SIB	a blood relation
SIM	short for Simeonite, an evangelical
SIS+	a contraction of sister
SNY+    a side channel of a river
SOC	the right of holding a local court
SOH	a musical note (also SOL)
SOL	same as SOH, above
SOU	an old small French coin
SOV	short form of sovereign, a gold coin
SOY	dark, salty sauce made from fermented beans

TAD	a small amount
TAI	a Japanese sea bream
TAK	Scots form of take
TAM	a cap with a broad, circular flat top
TAO	a path of virtuous conduct in Japanese philosophy
TAU	a letter of the Greek alphabet
TAV	a Hebrew letter
TAY	dial. for tea
TEF	an Ethiopian cereal grass
TEG	a heep in its second year
TEL	in Arab countries, a hill or mound
TET	a Hebrew letter (also TETH)
TIC	an involuntary twitching of muscles
TID	Scots word meaning mood
TIL	sesame	
TOC	telecommunications code for the letter 'T'
TOR	a hill
TUM	colloq. word for stomach

UDO	a Japanese species of aralia
UGH	an old representation of a cough or grunt
UNI	colloq. for university
URB	an urban area
URD	an Indian bean
URE	an extinct wild ox
UTA	any of a genus of large lizards
UTE	a short form of utility, a small truck
UTU	a Maori settlement of a debt

VAE	in Orkney or Shetland, a bay or creek (also VOE)
VAR	a unit of reactive power
VAS+	a duct carrying liquid 
VAW	a Hebrew letter (also VAV)
VEE	the letter 'V'
VID	short form of video
VIN	wine (Fr.)
VIS+	Latin word for force
VOE	same as VAE, above
VUG	a cavity in a rock

WAB	a web
WAE	Scots for woe
WAT	a Thai Buddhist temple or monastery
WAW	Spens. for wave
WEM	old word for wame, the womb or belly	
WEN	a sebaceous cyst
WEY	a measure for dry goods
WOK	a pan used in Chinese cookery
WUS+	a Welsh term used for addressing a companion
WYE	the letter 'Y'

YAH	a variant of yea, an affirmative vote
YAY	an affirmative vote (also YEA)
YEA	same as yay, above
YEP	a variant of yes (also YUP)
YEW	a type of evergreen tree
YID	an offensive term for a Jew
YIN	one of two opposing principles of Chinese philosophy
YOB	a lout
YOD	a Hebrew letter
YUG	one of the four hindu ages of the world (also YUGA)	
YUP	same as YEP, above

Non-Hook Threes Which can be Pluralised with (E)S

AUF	an elf's child
AUK	a type of sea-bird
AVA	an aromatic plant of the pepper family (also KAVA)
AVE	a recitation of the prayer to the Virgin MAry
AVO	a monetary unit of Macao
BRA	short form of brassiere
BRO	a place for which one feels a strong affinity
BUB	colloq. for baby
CIG	short for cigarette
COL	a pass in a mountain range
CRU	a vineyard (Fr.)
CWM	a Welsh word for valley
ECU	a European unit of currency
EWT	an old form of newt, a tailed amphibious animal
FIL	the shaft of a vehicle
FLU	a short form of influenza
FRA	Italian for brother
FUD	a rabbit or hare's tail
GAU	a German political district of the Nazi regime
GEO	same as GIO, GOE (a gully or creek)
GYM	a short form of gymnasium
HUI	a Maori gathering
KIR	a wine and blackcurrant drink
KUE	the letter Q
LEI	a garland or wreath
LEY	same as LEA (a meadow)
LUD	an old form of lord
LUV	love, as a term of endearment
LYM	Shak. for lyam, or leash
OCA	a South American wood-sorrel
OKE	a Turkish weight
OLE	a shout of approval
OLM	a blind salamander
PRO	a short form of professional, or prostitute
PUD	colloq. for pudding
PUL	a coin of Afghanistan
PUY	a small volcanic cone
RHY+	Spens. spelling of rye
RIA	a drowned valley
ROC	an enormous bird of Arabian legend (also ROK, RUC)
ROK	same as ROC, above
RUC	same as ROC, above
SEC	a secant
SEG	a stud in the sole of a shoe
SEI	a whale, a kind of rorqual
SEY	a part of a carcase of beef
SRI	sir, used aa a Hindu title of respect
SUD	a rare singular form of suds
SUK	same as SUQ, SOUK (a market place)
SWY+	an Australian two-up game
TUI	a New Zealand bird
TWA	Scots. form of two
TYG	an old drinking-cup with two or more handles
UEY	a U-turn
UFO	an unidentified flying object
UKE	a ukulele
ULE	a Central American rubber tree
ULU	an Eskimo knife
UVA	a grape or grape-like berry
VAU	an obsolete letter in the Greek alphabet
VAV	a Hebrew letter
VEG+	short for vegeatable
VIG	a vigorish, a charge paid to a bookie on a bet
VLY+	low-lying wet ground, a swamp
VOL	in heraldry, two wings displayed and conjoined
WYN	a rune, having the value of modern English 'w'

Threes Having Unusual 'S' Plural Forms

ALL	the whole; everything and everybody
AND	the symbol ampersand; something added
ARE	a unit of metric land measure
ATE	reckless ambition that drives one to ruin
BAD 	something that is evil
DRY	a prohibitionist (pl. DRYS)
DUG	the teat or udder of a female mammal
FED  	U.S. slang for federal agent
GAY	a homosexual
HOW	a manner or means
LAX+	a kind of salmon
LIT	the litas (monetary unit of Lithuania)
MET	a short form of meteorology
MID	short for midshipman; the middle
NIL	nothing
NOW	the present time
OLD	an individual of a specified age
PRY	(in plural form, PRYS) an old form of price
RAW	a sore or irritated spot
SHE	a female
VIA	a Latin word for road
WHY	the reason or cause of something (pl. WHYS)