From BiblePortal Wikipedia

King James Dictionary [1]

Could pron. COOD. The past tense of can, according to our customary arrangement in grammar but in reality a distinct word, can having no past tense. Could, we receive through the Celtic dialects.

1. Had sufficient strength or physical power. A sick man could not lift his hand. Isaac was old and could not see. Alexander could easily conquer the effeminate Asiatics. 2. Had adequate means or instruments. The men could defray their own expenses. The country was exhausted and could not support the war. 3. Had adequate moral power. We heard the story, but could not believe it. Th intemperate man could have restrained his appetite for strong drink. He could have refrained, if we would.

My mind could not be towards this people.  Jeremiah 15 .

4. Had power or capacity b the laws of its nature. The tree could not grow for want of water. 5. Had competent legal power had right, or had the requisite qualifications. Formerly, a citizen could not vote for officers of government without the possession of some property. AB could not be elected to the office of senator, for want of estate. BC, not being the blood of the ancestor, could not inherit his estate. 6. Had sufficient capacity. The world could not contain the books.  John 21 . 7. Was capable or susceptible, by its nature or constitution, as of some change. He found a substance that could not be fused. 8. Had adequate strength or fortitude as, he could not endure the pain or the reproach. 9. Had motives sufficient to overcome objections. He thought at first he could not comply with the request but after consideration he determined to comply. 10. Had competent knowledge or skill. He could solve the most difficult problems.

Vine's Expository Dictionary of NT Words [2]

1: Ἔχω (Strong'S #2192 — Verb — echo — ekh'-o )

"to have," is rendered "could" in  Mark 14:8 , "she hath done what she could," lit., "she hath done what she had." See Have.

2: Ἰσχύω (Strong'S #2480 — Verb — ischuo — is-khoo'-o )

"to have strength," is translated in  Mark 14:37 "couldest thou not." See Able.

 Acts 22:11Behold.Can

Webster's Dictionary [3]

(1): (imp.) Was, should be, or would be, able, capable, or susceptible. Used as an auxiliary, in the past tense or in the conditional present.

(2): (imp.) of Can