Meanings

three kinds of harmful friends: hypocritical, sycophantic, and glib-talking ones

MMR vaccine (for measles, mumps and rubella)

third-rate company director

3D printer

baseball played without a second base (children's game)

triplet

three great nobles of the Restoration

three great people (e.g. of the Meiji Restoration)

Spring Triangle (asterism)

Winter Triangle (asterism)

Summer Triangle (asterism)

15th day of the 1st, 7th and 10th lunar months

piano trio

even small mistakes can be costly

petty officer third class (USN)

the three friends of winter (pine, bamboo and plum)

killing three birds with one stone

kitchen maid

third gender

cholera