ponder
To ponder is to weigh. The mental sense — turn a thing over in the mind, hold it in suspense, give it its due gravity — is a metaphor laid directly over a scale. Latin ponderare, "to weigh," is built on pondus (stem ponder-), "weight," which belongs to the pendere family — "to hang, to weigh, to pay." (You weighed coin to pay it; the senses are one.) The metaphor was already complete in Latin: ponderare meant both "to weigh on a balance" and "to consider." English kept only the figurative half — we no longer ponder a sack of grain — but the literal weight is still inside the word, and surfaces undisguised in its closest cousin, ponderous: heavy.
To ponder is to weigh. The word is Latin ponderare, "to weigh," built straight on pondus, "weight," and the move from the balance to the mind was already finished by the time the Romans were using it — ponderare named both the physical act on the scale and the mental act of giving a matter its due consideration. English took the second sense and dropped the first. We no longer ponder a quantity of metal; we ponder a decision, a possibility, a grief. But the scale never left the word. To ponder a thing is to put it in one pan and hold it against the weight of everything else, and to wait, while the beam settles, for which way it tips.
Pondus belongs to a wide and tangled Latin family built on pendere, "to hang" — and the link between hanging and weighing is the balance itself, the thing suspended from a beam so its weight can be read. The same root that gives pendant and pendulum and suspend (things that hang) gives pension and expend and stipend (things paid) — because you paid by weighing out metal, and to weigh and to pay were one act. The word for thinking-it-over and the word for paying-it-out are cousins: both are forms of weighing.
The most beautiful cousin hides in plain sight. Pensive — "thoughtful, wrapped in thought" — is from pensare, the frequentative of pendere: "to weigh repeatedly," to keep weighing. And pansy, the flower, is from the French pensée, "a thought" — the bloom was named for thought, and the thought was named for weighing. So the pensive face and the garden pansy are both, underneath, the same act ponder names: a thing held in the balance of the mind. This is the elegant true cognate, the one you would suspect of being a folk-etymology and find, when you check, is real.
And here the entry has to be careful, because the deep root is exactly where false cousins breed. Etymonline files ponder under a broad PIE *(s)pen-, "to draw, stretch, spin," and sweeps spider, spin, and spindle into the same family — so that, on its account, a spider (the spinner, the one who draws out thread) is your cousin when you ponder. The more cautious reconstruction splits them: de Vaan gives the pendere / pondus branch a narrower root, *(s)pend-, "to stretch, pull," and notes it is only possibly a reshaping of the spinning root, "not identical to it." So the spider is a cousin of ponder only under the lumping — flag it, do not assert it. The genuine false friends are cleaner: pond (a variant of an enclosure-word, no weight in it), pundit (Sanskrit paṇḍita-, "a learned man"), pontoon (Latin pons, "bridge"). And the trap doubled inside one spelling: the pound that is a unit of weight is a true cousin of ponder — a Latin loan from pondō, "by weight" — but the pound that means "to strike, to crush" is native Germanic, a different word entirely. One weighs; the other beats. Only the weighing is kin.
- ponderous — Latin ponderosus, "of great weight; full of meaning," from pondus; the cousin that kept the literal "heavy" sense English ponder let go. The body of the weight, where ponder is its shadow in the mind
- pensive — Old French pensif, from penser, "to think," from Latin pensare, the frequentative of pendere, "to weigh"; the thoughtful face, literally "weighing things over and over"
- pansy — Old French pensée, "a thought, a remembrance," from penser, "to think"; the flower named for thought, the thought named for weighing — the elegant true cognate
- pension / stipend / expend / compendium — the "pay" branch of pendere; you paid by weighing out metal, so the words for money are the words for weight. Stipend is literally "a small payment" — Latin stips, "a small coin, alms," + pendere, "to pay by weighing out"
- pendant / pendulum / suspend / depend — the "hang" branch of pendere; the things that hang, including the balance from which weight is read
- poise — Old French pois, "weight," from pensum (a thing weighed out); to be poised is to be balanced — the scale's own equilibrium, made a virtue
- pound (unit of weight) — Old English pund, a loan from Latin pondō, "by weight" (ablative of pondus); a true cousin of ponder, shared at the root — only the weight-and-money pound, not the next entry
- pound (to strike, crush) — different root — Old English pūnian, native Germanic; a homograph of the weight-word but unrelated. The trap inside one spelling: one pound weighs, the other beats
- pond — different root — a variant of pound, "an enclosed place" (compare impound); no connection to Latin pondus, "weight." Surface coincidence
- pundit — different root — Hindi paṇḍit, from Sanskrit paṇḍita-, "a learned man, scholar"; sounds like "one who ponders," but an Indo-Aryan word with no Latin in it
- pontoon — different root — Latin pontonem, from pons, "bridge" (PIE *pent-, "to tread, go"); shares the pon- look, carries no weight
- spider / spin / spindle — contested — cousins of ponder only under Etymonline's broad *(s)pen-; the narrower *(s)pend- (de Vaan) keeps the spinning words on a separate, related root. Flag, do not weld