Given that we appear to be about evenly divided between UK and US folks (and given that "Britain and the United States are two countries divided by a common language"), there should be a dictionary of regional differences in bike terms. The main differences seem to be American English and UK/AU/NZ English.
UK: track pump / US: floor pump -- In the US, "track pump" is usually only used for a specific style of pump seen at a track, while in the UK it's commonly used to refer to any kind of floor pump. In Canada both are commonly used, although floor pump may be more familiar to those new to cycling.
US/CA: Spandex = UK: Lycra -- They're different brand-names for the same fibre (elastane)
US: wind vest or vest / UK: gilet (said "jee-lay") These are generally armless.
US: water bottle / UK: bidon (said "bee-don").
US/CA: public transit / UK: public transport. Suggest using "public transportation".
US/CA: Yield / UK: Give Way
US/CA: Flat / UK: Puncture -- In the US "puncture" refers only to tire/tube damage from piercing, such as a nail. In the UK "puncture" is also used for pinch flats, valve failures, etc.