A suffix of nouns of French or other Romance beginning, as accolade, ambuscade, brigade, cannonade, lemonade, etc., or of (a couple of) English nouns formed on a single design, as blockade, orangeade.
A suffix of nouns of Spanish or Italian source (originally masculine type of preceding), as brocade, renegade, etc. Moreover it appears when you look at the Spanish form -ado, such as renegado, desperado.
A suffix of Greek source, now generally -ad, as with decade (often decad), nomade (usually nomad, like monad, triad, etc.).