From Middle English od, odde (“odd, single”), from Old Norse oddi (“third or additional number, triangle”), from oddr (“point of a weapon”), from Proto-Germanic *uzdaz (“point”), from Proto-Indo-European *wes- (“to stick, prick, pierce, sting”) + Proto-Indo-European *dʰe- (“to set, place”). Cognate with Icelandic oddi (“triangle, point of land, odd number”), Swedish udd (“a point”), Old English ord (“a point”). More at ord.
odd (not generally comparable; comparative odder, superlative oddest)
- (not comparable) Single; sole; singular; not having a mate.
- Optimistically, he had a corner of a drawer for odd socks.
- (obsolete) Singular in excellence; unique; sole; matchless; peerless; famous.
- Singular in looks or character; peculiar; eccentric.
- Strange, unusual.
- (not comparable) Occasional; infrequent.
- But for the odd exception.
- (not comparable) Left over, remaining when the rest have been grouped
- I'm the odd one out.
- (not comparable) Casual, irregular, not planned.
- He's only worked odd jobs.
- (not comparable, in combination with a number, not comparable) About, approximately.
- There were thirty-odd people in the room.
- (not comparable) Not divisible by two.
- (not having a mate): single, mismatched
- (strange): bizarre, peculiar, queer, rum, strange, unusual, weird, fremd
- (about): about, approximately, around
- See also Wikisaurus:strange
- (not divisible by two): even
Derived terms 
rare: but for the odd exception
left over after others have been grouped