cleome
n.
5ModL6 any of a large genus (Cleome) of mostly tropical plants of the caper family, with white, pink, yellow, green, or purple flowers having stalked petals and long stamens; spider flower: see BEE PLANT

commensal
n.
5ME < ML commensalis < L com3, with + mensa, table: see MENSAL16
1 a companion at meals
2 Biol. either of the organisms living in commensalism
adj.
designating, of, or like a commensal
com[men4sal[ly

commutative
adj.
1 of commutation; involving exchange or replacement
2 Math. of or pertaining to an operation in which the order of the elements does not affect the result, as, in addition, 3 + 2 = 2 + 3 and, in multiplication, 2 1 3 = 3 1 2

oncho[ogy
n.
5see CONCH & 3LOGY6the branch of natural history that deals with the shells of mollusks
con[chol$o[gist
n.

mollusk
n.
5Fr mollusque < ModL Mollusca, coined by CUVIER < L mollusca, a soft-shelled nut < molluscus, soft < mollis: see MOLLIFY6 any of a large phylum (Mollusca) of invertebrate animals, including the chitons, gastropods, cephalopods, scaphopods, and bivalves characterized by a soft, unsegmented body, typically enclosed wholly or in part in a mantle and a calcareous shell, and usually having gills and a foot
mol[lus[kan 7m! lus4k!n8
adj., n.

precession
n.
5ME < LL praecessio < L praecedere, to PRECEDE6
1 the act of preceding; precedence
2 Astronomy short for PRECESSION OF THE EQUINOXES
3 Mech. an effect exhibited by a spinning body, as a top, when an applied torque tends to change the direction of its rotational axis, causing this axis generally to describe a cone and to turn at right angles to the direction of the torque
pre[ces4sion[al
adj.
From the Just So Stores, The Elephant's Child
"One fine morning in the middle of the Precession of the Equinoxes this 'satiable
Elephant's Child asked a new fine question that he had never asked before. He asked,
'What does the Crocodile have for dinner?' Then everybody said, 'Hush!' in a loud and
dretful tone, and they spanked him immediately and directly, without stopping, for a long
time. "

"That very next morning, when there was nothing left of the Equinoxes, because the
Precession had preceded according to precedent, this 'satiable Elephant's Child took a
hundred pounds of bananas (the little short red kind), and a hundred pounds of
sugar-cane (the long purple kind), and seventeen melons (the greeny-crackly kind), and
said to all his dear families, 'Goodbye. I am going to the great grey-green, greasy
Limpopo River, all set about with fever-trees, to find out what the Crocodile has for
dinner.' And they all spanked him once more for luck, though he asked them most
politely to stop. "

I was glad my kids did not demand that I explain about the Precession of the Equinoxes.

A repeat, but I had forgotten it. perhaps others have also.
procryptic
adj.
5< PRO(TECT) + CRYPTIC6 Zool. having protective coloration

A botanical term, but I could not be sure it was not an architectural term.
protostele
n.
5PROTO3 + STELE6 a simple, primitive arrangement of conducting tissues in stems and roots of certain lower plants, consisting of a solid cylinder of xylem surrounded by a layer of phloem
pro#to[ste4lic
adj.

Not a preconceived delusion. More like a prelude.
prolusion
n.
5L prolusio, prelude < prolusus, pp. of proludere, to play beforehand < pro3, before + ludere, to play: see PRO32 & LUDICROUS6a preliminary part or performance; often, specif., an introductory essay or article
pro[lu4so[ry 73s! rc8
adj.

Not the result of a kick in the buttocks.
psoas
n.,
pl. psoas pl. of Gr psoa, muscle of the loins6 either of two muscles attached to the lower spinal column, esp. the one that controls certain movements of the thigh
pso[at[ic 7sb at4ik8
adj.
This is what I think the butchers call "the eye of the round".