Etymology
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armada (n.)
"fleet of warships," 1530s (armado), from Spanish armada "an armed force," from Medieval Latin armata "armed force" (see army). Current form of the word is from 1590s. The fleet sent by Philip II of Spain against England in 1588 was being called the Spanish Armada by 1613, the Invincible Armada by 1632.
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invincible (adj.)

early 15c., from Old French invincible (14c.) or directly from Latin invincibilis "unconquerable," from in- "not" (see in- (1)) + vincibilis "to be gained, easily maintained, conquerable," from vincere "to overcome" (from nasalized form of PIE root *weik- (3) "to fight, conquer"). Related: Invincibly.

The noun meaning "one who is invincible" is from 1630s. Invincible ignorance, an ignorance which the person having it lacks means to overcome, is from Church Latin ignorantia invincibilis (Aquinas). The Invincible Armada was the Spanish of 1588. Related: Invincibly.

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