clover
deuce-ace
leash
set of three
shamrock
tercet
ternary
ternion
terzetto
three
threesome
tierce
trey
triad
trialogue
triangle
tricorn
trident
triennium
trihedron
trilogy
trimester
trine
trinity
trinomial
trio
triphthong
triple crown
triple threat
triplet
triplopy
tripod
triptych
trireme
triseme
triskelion
trisul
triumvirate
triunity
trivet
troika
medic
architectural ornament
alfalfa
cinquefoil
heartshaped
huitfoil
mome
plantain
purl
quatrefoil
rye-grass
saintfoin
sexfoil
timothy
vert