canaliculus

This term is used almost exclusively in anatomical and histological contexts to describe microscopic channels. It carries a highly technical register, typically appearing in medical textbooks, pathology reports, or biological research papers rather than general conversation.

Because it is derived from Latin, the word follows a specific irregular pluralization pattern. Instead of adding a standard English suffix, the ending changes to -uli, which is a hallmark of Latin second-declension nouns.