Source : Webster's Revised Unabridged Dictionary (1913)
-er \-er\
.
1. [AS. -ere; akin to L. -arius.] The termination of many
English words, denoting the agent; -- applied either to
men or things; as in hater, farmer, heater, grater. At the
end of names of places, -er signifies a man of the place;
as, Londoner, i. e., London man.
2. [AS. -ra; akin to G. -er, Icel. -are, -re, Goth. -iza,
-?za, L. -ior, Gr. ?, Skr. -[=i]yas.] A suffix used to
form the comparative degree of adjectives and adverbs; as,
warmer, sooner, lat(e)er, earl(y)ier.