A 7 letter word starting with c is confirm.
cavemen, catwalk, caskets, catcher
vocalic or voltaic.
convene also collect
Cash is a 4 letter word that starts with c and ends with h.
A science word that is six letters ans starts with the letter c is convex.
coxcomb
Chronic
chaotic
czarism
Company
CHARITY
Cantata
success
compass
vocalic or voltaic.
Cryptic
Cabanas, Cablets, cackles
citedal