The words Protostome and deuterostome are missing .
Sciences (real and wannabe) give birth to an impressive number of arcane-sounding words, some of which seldom cross the thresholds of laboratories or university classrooms - and when they do they usually land in an AI database or in the mouth of simpletons persuaded that just uttering them suffices to sound important.
Whether adding such words to a dictionary would enrich or just clutter it, is an open question and possibly also a matter of taste (see here).
Just for fun I spent (wasted?) a few free minutes writing down some words that I would not insert in a sensible dictionary as they belong exclusively in specialized tomes, strictly professional conversations and (of course) wikipedia:
glycosylation, phonon, morula, epigenesis, pareidolia, haecceity, allomaternal, supersymmetry, nabla
Rest assured that they all exist in English - but who would ever look them up in a non-specialized dictionary?
Besides, what should we do with all those scientific terms that include a proper name, such as “Cherenkov radiation”, “Golgi apparatus”, “Leydig cells.”“Kipp’s apparatus”, “islets of Langerhans”, Maxwell’s equations", “Heisenberg’s principle”?
It doesn’t hurt to bear in mind that there is a difference between a dictionary and an encyclopedia.