The general wisdom of language/library design is that abbreviations should be used only for very common things, and only when those abbreviations are unambiguous in context. Prehistoric Rust had a rule that all keywords could be no longer than five characters (in defiance of Javascript's `function`), but forums (including HN) endlessly complained about `ret`, hence today it's `return`. :P (I admit that I wanted to Rust to change its `fn` to `func` once Swift showed its hand, but such is life.)
Meanwhile, in 2020 `Option` might be on its way to becoming a widely-accepted concept in language design, but back in 2011 it was still a radical idea that Rust was trying to smuggle over the border from functional languages, against the will of people used to languages with pervasive nullity. The language that eventually supplants Rust someday might call it `Opt` (in the same way that Rust turned C++'s `vector` into `Vec`), but back then `Option` needed all the lubrication it could get without having to get bogged down in the abbreviation bikeshedding.
Meanwhile, in 2020 `Option` might be on its way to becoming a widely-accepted concept in language design, but back in 2011 it was still a radical idea that Rust was trying to smuggle over the border from functional languages, against the will of people used to languages with pervasive nullity. The language that eventually supplants Rust someday might call it `Opt` (in the same way that Rust turned C++'s `vector` into `Vec`), but back then `Option` needed all the lubrication it could get without having to get bogged down in the abbreviation bikeshedding.