I have used the word 'bike' to address motorcycle in past. In recent years though, I noticed that this word is being used more for a bicycle than for a motorcycle. Since then I just 'assumed' that it should not be used for motorcycles. I tried to reason it (to myself) by (again) assuming that bike is a word evolved from bicycle (eg. to shorten it). When I searched for in on the Internet, I found that both of above assumptions are baseless and probably wrong. It does show as its meaning, motorcycle, and also it doesn't hint that it's originated from the word bicycle. Can anyone clear these questions? Does bike mean motorcycle as well? If not, is it plain wrong to use it that way? What is the origin of the word 'bike'?
Bike derives from bicycle:
1882, American English, shortened and altered form of bicycle (n.). As a verb by 1895. (Etymonline)
But bike is used as a short for both bicycle and motorbike:
A bike is a bicycle or a motorcycle. (Informal)- (Collins)
and also biker:
a member of a group of people riding motorcycles: We were passed by a crowd of bikers doing over 90 mph.
someone who rides a bicycle