I'm skeptical of single definitions without disclaimers.
At the meta-level it isn't clear what value other definitions might offer (in this case). ("Truth" seems like a basic concept that is understood prior to reading that article - it's easier to imagine such an argument for other concepts without such wide understanding.)
Most dictionaries have multiple definitions for words. This seems more like what we should aim for.
Perhaps more definitions should be brought in (as necessary), with the same level of attention to detail -
I'm sure that others, including others on LessWrong, have used it differently.
when they are used (extensively). It's possible that relevant posts have already been made, they just haven't been integrated into the wiki. Is the wiki up to date as of 2012, but not after that?