Relating to or of the nature of an appendix; having the quality of being appended or attached.
From Latin appendix + -ial (variant of -al). This form represents an attempt to create yet another adjective variant from appendix, showing the proliferation of near-synonyms in technical terminology.
We now have appendical, appendicial, appendiceal, and appendicular—four adjectives from one noun! This explosion of variants happened because medical specialists wanted precise distinctions, but now we're stuck with redundancy.
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