Back means the rear of something.

Children should sit in the back of the car.

Dèyè vle di do yon bagay.

Timoun yo dwe chita dèyè machin nan.

the space or position at the back of something or someone

My back is sore, I need a massage.

espas ki genyen oswa pozisyon ki nan do yon bagay oswa moun

Mwen malad nan do, mwen bezwen yon masaj.

the rear surface of the human body from the shoulders to the hips:

Oliver slapped me on the back

sifas dèyè nan kò imen an soti nan zepòl yo rive nan ranch yo

Oliver ap banm tap nan do.

to return to an earlier or normal position or condition

I leave home every Monday morning, and I get back every Friday night.

tounen nan yon pozisyon pi bonè oswa yon kondisyon nòmal

M kite lakay chak lendi maten, m retounen chak vandredi swa.

the posterior part of a human (or animal) body from the neck to the end of the spine

He lay on his back.

pati postè yon moun (oswa bèt) kò ki soti nan kou a jiska lafen kolòn vètebral

Li kouche sou do l.