The meaning of this word according to the "The American Heritage Dictionary" is 1. Preservation or deliverance from evil or difficulty. 2. The deliverance of man or his soul from the power or penalty of sin.
The word salvation in Gen. 49:18 in the Hebrew language is (yeshooaw, yeshuah). The word yesha means free or to be safe, that is rescue, save give victory. In another words the meaning of (yeshuah) is  deliverance, victory, prosperity, health, help or salvation. The meaning changes depending on the trouble you fall in, or the danger that is facing you. If you are sick to be saved is to be healed, if you are fighting to be saved is to have victory, if you are in prison to be saved is to be set free, that is to deliver. If you are going to face eternity in hell and the lake of fire than to be saved is not to go there.

The translation of this word  in Gen. 49:18  (yeshooaw, yeshuah) to the Greek language is according to the Septuagint translation is (sotayreeah). The meaning of the word in Greek carries the same meaning as in Hebrew.

All the people living on the earth and those who lived before have sinned. The Bible the Word of God says "All have sinned and come short of the glory of God." Rom. 3:23 Also the Bible says "The wages of sin is death..." Rom. 6:23  If all the people sinned and the wages of sin is death. This is a problem to all the people. The problem is how to escape the penalty of sin. How could we solve the problem "the wages of sin is death."? Either I die or some one have to die for me. Who can die for my sins?  The one who will die for my sin must be sinless or else he have to face the death himself like everybody. 

The Lord Jesus Christ was born of a virgin and lived a sinless life and he died on the cross to take away the sin of the world. "... Behold the Lamb of God, which taketh away the sin of the world." John 1:29