Calycinal is an uncommon word that describes an important part of sea urchin anatomy. However, if you're looking for synonyms for this term, you might consider the following: peristomial, ambulacral, and epistomal. Each of these terms refers to a different aspect of sea urchin anatomy, and can be used interchangeably with calycinal in different contexts. For example, peristomial means "around the mouth", while ambulacral refers to the channels that transport water through the sea urchin's body. By learning alternative synonyms for these terms, you can expand your vocabulary and better understand the complex biological concepts that they describe.