From The Collaborative International Dictionary of English v.0.48:
Er \Er\ n.
the chemical symbol for erbium, a rare earth element. It
has atomic number 68 and an atomic weight of 167.26.
Syn: erbium.
[WordNet 1.5 +PJC]
From The Collaborative International Dictionary of English v.0.48:
-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.
[1913 Webster]
2. [AS. -ra; akin to G. -er, Icel. -are, -re, Goth. -iza,
-?za, L. -ior, Gr. ?, Skr. -[imac]yas.] A suffix used to
form the comparative degree of adjectives and adverbs; as,
warmer, sooner, lat(e)er, earl(y)ier.
[1913 Webster]