Extraneous means not belonging to the matter in hand. Extraneous detail, extraneous noise, strip out the extraneous.
It is the editor's word for what should come out, and in experiments it names everything that must be controlled for. It is a doublet of strange, and both mean something from outside.
1adjectiveextraneousNot belonging to the matter in hand.
“Cut out any extraneous details so the report is short and clear.”
extraneous is a quality.
Latin extraneus means from outside, from extra, outside; strange is a doublet.
Latin
extrāneus — from without, strange
English, today
extraneous
From Latin extrāneus (“from without, strange”). a doublet of strange. Cognate with estrange, Spanish extraño.
Etymology from Wiktionary, CC BY-SA