Origins
The word 'pertain' entered English in the early fourteenth century from Old French 'partenir' (later influenced by the Latin spelling to become 'pertenir'), descended from Latin 'pertinēre,' meaning 'to reach to,' 'to extend to,' 'to belong to,' or 'to relate to.' The Latin verb combines 'per-' (through, thoroughly) with 'tenēre' (to hold), from PIE *ten- (to stretch). The literal image is of something that holds through — a connection that extends from one thing to another, linking them.
In Latin, 'pertinēre' had a remarkably broad range. Cicero used it in the sense of 'to relate to' or 'to concern': 'quod ad rem pertinet' (what pertains to the matter). It could also mean 'to extend physically': 'ager ad flumen pertinet' (the field extends to the river). And it could mean 'to belong to' in the sense of being part of something: 'haec ad te pertinent' (these things belong to you, these concern you). All three senses entered English and remain in use.
The derivative 'pertinent' (relevant, to the point) preserves the Latin participial form 'pertinēns.' Its negative 'impertinent' underwent a striking semantic shift. In its original fifteenth-century English usage, 'impertinent' simply meant 'not pertinent' — irrelevant, beside the point. A judge might dismiss 'impertinent' testimony that did not relate to the case. Over the next two centuries, the word shifted from 'irrelevant' to 'presumptuous' or 'insolent.' The logical bridge was social context: making remarks that did not pertain to the conversation was seen as a breach of decorum, hence rudeness. By the seventeenth century, 'impertinent' primarily meant 'rude' or 'insolent,' and the original meaning of 'irrelevant' had largely faded.
French Influence
The related verb 'appertain' (from Old French 'apertenir,' from Latin 'appertinēre') carries the same basic meaning as 'pertain' but with a slightly more formal and archaic flavor. Legal texts particularly favor 'appertain': 'all rights and privileges appertaining thereto.' The 'ap-' prefix (a variant of 'ad-,' meaning 'to') emphasizes the direction of the connection: belonging to, reaching toward.
Within the '-tain' family, 'pertain' occupies a distinctive semantic niche. While 'sustain,' 'maintain,' 'obtain,' and 'attain' all involve active holding — supporting, keeping, acquiring, reaching — 'pertain' involves relational holding. It does not describe an action so much as a connection. Things that pertain to a subject are held in relation to it — they reach through to it, they touch it, they are relevant to it.
The word appears frequently in legal, academic, and formal contexts: 'pertaining to the terms of the agreement,' 'documents pertaining to the case,' 'regulations pertaining to food safety.' In everyday speech, 'relate to' or 'concern' often substitute, but 'pertain' carries a precision and formality that its synonyms lack. Its etymology — holding through, reaching to — gives it a sense of genuine connection rather than casual association.