greatest (Adjective) — Highest in quality.
greatest (Adjective) — Very good. ex. "had a great time at the party"
greatest (Adjective) — Relatively large in size, number or extent; larger than others of its kind. ex. "a great juicy steak" ex. "a great multitude" ex. "the great auk" ex. "a great old oak" ex. "a great ocean liner" ex. "a great delay"
greatest (Adjective) — Of major significance or importance. ex. "a great work of art"
greatest (Adjective) — Remarkable or out of the ordinary in degree or magnitude or effect. ex. "a great crisis" ex. "had a great stake in the outcome"
greatest (Adjective) — Uppercase. ex. "great A"
greatest (Adjective) — In an advanced stage of pregnancy. ex. "was great with child"