What is the meaning of Caer?

A Welsh fortress.

alternative form of cayer

to fall, fall off, fall down

to fall on; to occur

to fall; to decline; to collapse

to fall; to die in battle

to fall (to move to a lower position due to gravity)

to fall (to come down, to drop, to descend)

to fall down, to collapse (to fall to the ground)

to fall out (to come out of something by falling)

to fall into, to fall for; to be ensnared by

to fall into (to enter a negative state)

to fall, to collapse (to be overthrown or defeated)

to get (to understand)

to be granted, awarded, or given (potentially by chance)

to fall under (to belong to for purposes of categorization)

to fall on (to occur on a particular day)

fort, fortress, enclosed stronghold, castle, fortress, citadel, fortified town or city

wall, rampart, bulwark

twill

impersonal imperative of cael

Source: wiktionary.org