The American Heritage® Dictionary of the English Language: Fourth Edition. 2000.
Appendix I
Indo-European Roots
ENTRY:
smei-
DEFINITION:
To laugh, smile. 1.smirk, from Old English smercian, to smile (with -k- formative), from Germanic reshaped forms *smer-,*smar-.2.smile, from Middle English smilen, to smile, from a Scandinavian source probably akin to Swedish smila, to smile, from Germanic extended form *sml-.3. Suffixed form *smei-ro-.marvel, miracle, mirage, mirror; admire, from Latin mrus, wonderful. 4. Prefixed zero-grade form *ko(m)-smi-, smiling with (*ko-,*kom-, together; see kom). comity, from Latin cmis (< cosmis), courteous. (Pokorny 1. (s)mei- 967.)
l-. 3. Suffixed form *smei-ro-. marvel, miracle, mirage, mirror; admire, from Latin m
mis (< cosmis), courteous. (Pokorny 1. (s)mei- 967.) 
