What is Big and O in Big O notation? I've read the definitions and it doesn't tell what is O pronounced as 'oh'.  For example - I understand that O(n) is complexity of a linear algorithm where n could be the number of operations. but what is an O?
What is O in Big O?
complexity;etymology;notation;big o
Well, my guess would be order, which coincides with wikipedia.Edit: (my own (any improvements appreciated)) translation from the German wikipedia articleThe capital letter O (actually a capital omicron at the time) as a  symbol for the order of (German: Ordnung von) was first used by the  German number theorist Paul Bachman in the second  issue of his book  on analytic number theory appeared in 1894. The notation gained  popularity due to the work of Edmund Landau, another German number  theorist, whom this nomenclature is widely associated with today,  especially in the German terminology.