How do we handle plural and alternative spellings?

From HAO Wiki

Right now we can use 'tags' in mx - basically that means you are tagging a key word ('plural spelling') to a term and providing the content for that keyword. For example, the term 'fovea' can be tagged as having keyword 'plural spelling' with content 'foveae'. Is this sufficient? Or do we create a separate relationship called 'plural of' and enter both terms directly into the ontology?

This same question applies to adjectives as well (facial vs. face)