There are many sources that defines and explain the meaning of this word, but at this hour of this day I was reading Colossians 1 v 4, 5 and 6.
4: Since we heard of your faith in Christ Jesus, and of the love which ye have to all the saints.
5: For the hope which is laid up for you in heaven, whereof ye heard before in the word of the truth of the gospel.
6: Which is come unto you, as it is in all the world; and bringeth forth fruit, as it doth also in you, since the day you heard of it, and knew the grace of God in truth.
The Colossians have:
Faith in Christ
Love for all saints
Heard the truth of the gospel
Another translation explain faith as “leaning of your entire human personality on Jesus in absolute trust and confidence in His power, wisdom and goodness.”