The term ark is used in Scripture of two different objects as listed below.

This type of ark (Heb. tebah, "box" or "chest") refers to the huge, barge-like floating structure that Noah built according to God's commandment (Genesis 6:1-9:18). The ark was God's appointed means to save Noah and His immediate family and representative animals from God's judgment through the flood (Genesis 6:1-9:18; Matthew 24:38; Hebrews 11:7; 1 Peter 3:20).

This ark (Heb. tebah) refers to the small papyrus "basket" in which Moses' mother placed him "by the bank of the Nile" where Pharaoh's daughter found him (Exodus 2:3, 5).

Ark (Heb. aron, "chest" or "ark") is used most frequently in Scripture of the very significant article of furniture located in the "holy of holies" of the tabernacle (Exodus 26:33-34; 40:21; 1 Samuel 3:3; 2 Samuel 7:2; 1 Chronicles 16:1) and later in Solomon's temple (1 Kings 6:19; 8:6-9, 21; 1 Chronicles 22:19; 2 Chronicles 5:7). It was a rectangular chest made of acacia wood and overlaid with gold (Exodus 37:1-9). The ark measured approximately 45 x 27 x 27 inches (Exodus 37:1). A pole was slid through a pair of rings on each side of the ark to transport it (Exodus 37:3-5). Two cherubs hovered over it, and it had a lid or mercy seat where God specifically met with His people (Exodus 25:10-22; 37:6-9; Numbers 7:89; Hebrews 9:4-5). The mercy seat of the ark was sprinkled with blood by the high priest on the day of atonement (Leviticus 16:1-34, especially vv. 14-15; Hebrews 9:7, 25).

This topic is from the Lockman Foundation.