triangular prism

three years; the third year / (education) the third school year / (figuratively) a long period of time, several years

three years; triennial / three years old

three years of age, three years old

a bird in the hand is worth two in the bush

(obsolete) round the clock / (obsolete) all the time

somnambulism, sleepwalking

round the clock / all the time

a right-angled triangle

(phonetics) in Sanskrit phonology, a consonant produced using one of the three places of articulation: dorsal (/k, g, ŋ/), coronal (/t, d, n/), or labial (/p, b, m/)