Strong’s Dictionary of Greek Words:

from 1468; self-control (especially continence)
KJV Usage:

From Manners and Customs of the Bible:

1 Corinthians 9:25. Every man that striveth for the mastery is temperate in all things. Now they do it to obtain a corruptible crown; but we an incorruptible.
Among the four sacred games of the ancient Greeks, the Olympic and the Isthmian were the most celebrated, the former taking the precedence. To these familiar games the apostle makes many allusions in his writings. (See further, note on Heb. 12:1, #884.) There are two of such in this text.
1. Every competitor in these games was obliged to undergo a severe and protracted training, sometimes lasting nearly a year, during which time he carefully avoided excesses of every kind. A ‘passage from Epictetus so beautifully illustrates this text that it is cited by most commentators: “Would you be a victor in the Olympic games? so in good truth would I, for it is a glorious thing; but pray consider what, must go before, and what may follow, and so proceed to the attempt. You must then live by rule, eat what will be disagreeable, refrain from delicacies; you must oblige yourself to constant exercises at the appointed hour, in heat and cold; you must abstain from wine and cold liquors; in a word, you must be as submissive to all the directions of your master as to those of a physician” (Enchiridion, chap. 35).
Thus Paul says in the text: “Every man that striveth for the mastery is temperate in all things.”
2. The victor was rewarded with a crown or chaplet of leaves. The Olympic crown was made of the leaves of the wild olive, the Isthmian was made of pine or ivy. From the earliest periods of history chaplets of leaves were bestowed upon heroes who had conquered on the field of battle. Thus the Psalmist says of the triumphant Messiah: “Upon himself shall his crown flourish” (Psa. 132:18). The idea of a crown flourishing is very expressive when spoken of a leafy chaplet; though some commentators render the word shine. This is the sort of crown to which Paul refers in the text as “corruptible.” The crown of thorns which was placed on the Saviour’s head was a mockery of these wreaths of triumph, as well as of the golden crowns of kings. See Matthew 27:29; Mark 15:17; John 19:2,5.
The leafy crown given to the victor in these ancient games doubtless furnishes the metaphor which is used in 2 Timothy 2:5; 4:8; James 1:12; 1 Peter 5:4; Revelation 2:10; 3:11.