base, basis, foundation, ground, root / (construction, architecture) foundation

organization (a group of people with a purpose) / system (a group of people) / (biology) tissue (a group of similar cells that function together to do a specific job)

an ape, (in particular) a gibbon / aiming at / aiming for; in pursuit of something / waiting for an opening; awaiting one's chance

a manor, a villa / a village, a hamlet / number of mahjongg games (counter)

accuse, appeal, complain, sue

vinegar

oxygen (chemical element) / oxygen (molecular oxygen)

(chemistry) rare earth elements

an isotope

(chemistry) element, chemical element