1899, from combining form of tonsil + -ectomy "a cutting, surgical removal." A hybrid with a Latin front end and a Greek ending. A correct formation all from Greek would be amygdalectomy.
Entries linking to tonsillectomy
tonsil n.
c. 1600, from Latin tonsillae, tosillae (plural) "tonsils," diminutive of toles "goiter," which is perhaps of Gaulish origin. Related: Tonsils.
-ectomy
word-forming element meaning "surgical removal," from Latinized form of Greek -ektomia "a cutting out of," from ektemnein "to cut out," from ek "out" (see ex-) + temnein "to cut" (from PIE root *tem- "to cut").