The Catechism in Questions & Answers

101. How is it to be understood that the Son of God is described as the “Word” (“logos”)?

God created and ordered all things in a meaningful way through the Word (“Then God said...” Genesis 1: 3). Thus the Word is the source, from whom all things emanate.
The designation “Word” (= Greek logos) is also used for the Son of God in the first chapter of the gospel of John. This is a reference to the fact that God, the Son is just as much the Creator as God, the Father and God, the Holy Spirit.

“In the beginning was the Word, and the Word was with God, and the Word was God. He was in the beginning with God. All things were made through Him, and without Him nothing was made that was made. And the Word became flesh and dwelt among us, and we beheld His glory, the glory as of the only begotten of the Father, full of grace and truth.”
John 1: 1-3, 14