What is a two letter word beginning with c?

Answer 1

There's the proper name Cy, but most two-letter words are abbreviations.
ca -- circa, calcium, California
cb -- Citizen's Band
cc -- carbon copy, cubic centimeter, Cape Cod
cd -- compact disc, cadmium
ce -- cerium
cf -- Californium
cg -- centigram, Coast Guard
ch -- church, clearing house, custom house
ci -- cirrus, Curie, Channel Islands
cj -- Chief Justice
cl -- centiliter, chlorine
cm -- centimeter, curium
co -- cobalt, Colorado, company, conscientious objector
cp -- Cerebral Palsy, candlepower
cr -- credit, chromium
cs -- cesium, Civil Service
ct -- Connecticut
cu -- copper
cv -- curriculum vitae
cy -- calendar year