rock, rough

Concise Bible Dictionary:

Two words are principally employed for this word. One is sela, “an elevation of strength, immovable:” used symbolically for Jehovah as the rock of His people: “Jehovah is my rock and my fortress” (Psa. 18:22The Lord is my rock, and my fortress, and my deliverer; my God, my strength, in whom I will trust; my buckler, and the horn of my salvation, and my high tower. (Psalm 18:2)). He hath “set my feet upon a rock, and established my goings” (Psa. 40:22He brought me up also out of an horrible pit, out of the miry clay, and set my feet upon a rock, and established my goings. (Psalm 40:2)).
In the New Testament anyone who heard and did the sayings of the Lord is compared to a man who built his house upon the rock which nothing could shake (Matt. 7:24-2524Therefore whosoever heareth these sayings of mine, and doeth them, I will liken him unto a wise man, which built his house upon a rock: 25And the rain descended, and the floods came, and the winds blew, and beat upon that house; and it fell not: for it was founded upon a rock. (Matthew 7:24‑25); Luke 6:4848He is like a man which built an house, and digged deep, and laid the foundation on a rock: and when the flood arose, the stream beat vehemently upon that house, and could not shake it: for it was founded upon a rock. (Luke 6:48)). The Lord said, “Thou art Peter (πέτρος), and upon this rock (πέτρα) I will build My church.” The church is being built upon what Peter confessed, Christ Himself, the Son of the living God (Matt. 16:16-1816And Simon Peter answered and said, Thou art the Christ, the Son of the living God. 17And Jesus answered and said unto him, Blessed art thou, Simon Bar-jona: for flesh and blood hath not revealed it unto thee, but my Father which is in heaven. 18And I say also unto thee, That thou art Peter, and upon this rock I will build my church; and the gates of hell shall not prevail against it. (Matthew 16:16‑18); compare 1 Cor. 3:1111For other foundation can no man lay than that is laid, which is Jesus Christ. (1 Corinthians 3:11); 1 Cor. 10:44And did all drink the same spiritual drink: for they drank of that spiritual Rock that followed them: and that Rock was Christ. (1 Corinthians 10:4)).

Strong’s Dictionary of Greek Words:

Number:
5138 (find all occurrences in KJV Bible)
Greek:
τραχύς
Transliteration:
trachus
Phonic:
trakh-oos’
Meaning:
perhaps strengthened from the base of 4486 (as if jagged by rents); uneven, rocky (reefy)
KJV Usage:
rock, rough