strict

The word works on both sides of a rule. It describes the person who keeps one (they are very strict in observing the Sabbath, where strict in takes an -ing verb) and the rule itself, as when Baroness Orczy calls Mr. Keeson's orders very strict. Puritanical is a sharper near-synonym, and nice once carried this meaning too, now long obsolete. The discipline sense narrows it to keeping others in line.

Precision rather than severity is the point here. Strict watch and strict attention are close and unbroken, not harsh. The adjective works almost as an intensifier of care, and its nearest companions are thorough and correct. To tell it from the rule-enforcing meaning, ask whether anyone is being made to obey. If no one is, the word simply means exact.

Narrowing is the work done here: the word fixes limits and reads them tightly. Its home phrase is in a strict sense, used to set aside a looser everyday meaning in favor of the exact one. Narrow and proper are its close synonyms. Where the "exact" meaning concerns care in doing something, this one concerns where the boundaries of a meaning fall.

The physical sense the word began with comes from Latin strictus, "drawn tight", the past participle of stringere, "to bind, contract". Strait and stringent grow from the same root, and strong is a more distant relative. A strict ligature or a strict embrace squeezes; it does not discipline. Modern readers usually hear the rule-bound meaning first, so the surrounding sentence has to make the tightness unmistakable.

Order theory uses the word to strip out equality: a strict relation never holds between an element and itself. The paired symbols show it best, since < is the strict counterpart of ≤, and a strict partial order is a partial order with the reflexive case removed. Where a definition would otherwise make a relation reflexive, adding the adjective overrides that condition.

A botanist's word for growth habit, applied to stems or flower clusters held erect and narrow rather than spreading. It describes the overall shape a plant takes, and in plant descriptions it carries no hint of rules or discipline. The image is closer to the "drawn tight" meaning than to any modern use: the parts are held in close, as if bound.