Harmonize EIA definitions with Carpentries community glossary

### How could the content be improved?

The Equity, Accessibiilty and Inclusion episode [defines](https://carpentries.github.io/instructor-training/09-eia.html#definitions) EIA based on the U. Pitt. DEI glossary. However, as noted in the [2025-03-19 statement/blog](https://carpentries.org/blog/2025/03/the-carpentries-reinforced-commitment-to-inclusion-diversity-equity-and-accessibility/), our [community glossary ](https://github.com/carpentries/community-engagement/blob/main/glossary.md)has our own definitions.

There is a case to be made that some of the current definitions are more tightly coupled to the information in the episode and shouldn't change (or should change but with some modification), so I'm not proposing this as a PR until there's been some time for discussion.

### Which part of the content does your suggestion apply to?

https://carpentries.github.io/instructor-training/09-eia.html#definitions

Read the definitions section in episode 09-eia.html and compare it with community-engagement/glossary.md. First resolve which definitions should align with the community glossary and which need episode-specific wording; done means the agreed definitions are updated consistently after the discussion.

Written by the indexing model from the issue text.