Marginal

google

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late 16th century: from medieval Latin marginalis, from margo, margin- (see margin).

wiktionary

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Borrowing from Medieval Latin marginālis.

etymonline

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marginal (adj.)

1570s, "written or printed on the margin of a page," from Medieval Latin marginalis, from Latin margo "edge, brink, border, margin" (see margin (n.)). Sense of "of little effect or importance" first recorded 1887. Related: Marginally.