say it: AWN-lahyn
online is an adjective meaning "on a regular route of a railroad or bus or airline system". It carries 3 recorded senses.
on a regular route of a railroad or bus or airline system
“on-line industries”
transportation
connected to a computer network or accessible by computer
“an on-line database”
computer science
being in progress now
“on-line editorial projects”
Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.
Definitions, synonyms and semantic relations for online come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.