Webster's Revised Unabridged Dictionary · 1913

Broad

Broad (brad) , adjective

[Old English brod, brad, Anglo-Saxon brād; akin to Old Saxon brēd, Dutch breed, German breit, Icelandic breier, Swedish & Danish bred, Gothic braids. Compare Breadth.]

1.
Wide; extend in breadth, or from side to side; -- opposed to narrow; as, a broad street, a broad table; an inch broad.
2.
Extending far and wide; extensive; vast; as, the broad expanse of ocean.
3.
Extended, in the sense of diffused; open; clear; full.
Broad and open day. — Bp. Porteus
4.
Figuratively: Having a large measure of any thing or quality; not limited; not restrained; -- applied to any subject, and retaining the literal idea more or less clearly, the precise meaning depending largely on the substantive.
A broad mixture of falsehood. — Locke

Hence: -

5.
Comprehensive; liberal; enlarged.
The words in the Constitution are broad enough to include the case. — D. Daggett
In a broad, statesmanlike, and masterly way. — E. Everett
6.
Plain; evident; as, a broad hint.
7.
Free; unrestrained; unconfined.
As broad and general as the casing air. — Shakespeare
8.
(Fine Arts) Characterized by breadth. See Breadth.
9.
Cross; coarse; indelicate; as, a broad compliment; a broad joke; broad humor.
10.
Strongly marked; as, a broad Scotch accent.
It is as broad as long, whether they rise to others, or bring others down to them. — L'Estrange

Broad is often used in compounds to signify wide, large, etc.; as, broad-chested, broad-shouldered, broad-spreading, broad-winged.

Collocations (4)
Broad acres , See under Acre.
Broad arrow , originally a pheon. See Pheon, and Broad arrow under Arrow.
As broad as long , having the length equal to the breadth; hence, the same one way as another; coming to the same result by different ways or processes.
Broad pennant , See under Pennant.

Broad , noun

1.
The broad part of anything; as, the broad of an oar.
2.
The spread of a river into a sheet of water; a flooded fen. [Local, English] — Southey
3.
A lathe tool for turning down the insides and bottoms of cylinders. — Knight
4.
A woman, especially one who is sexually promiscuous; -- usually considered offensive. [slang]