which was the length of the arm from the tip of the finger to the elbow

One of the oldest units of measurement used in the ancient world was the cubit which was the length of the arm from the tip of the finger to the elbow.

18 inches

The note in the Companion Bible tells us that a cubit is 18 inches.

the length from your elbow to the end of your middle finger— about 18 inches

A “cubit” is the length from your elbow to the end of your middle finger—about 18 inches.

an ancient unit of length based on the distance from the elbow to the tip of the middle finger

The cubit is an ancient unit of length based on the distance from the elbow to the tip of the middle finger.

the measurement of a forearm, from fingertips to elbow

A cubit is the measurement of a forearm, from fingertips to elbow.

a cubit and a hand width

“And these are the measurements of the altar by cubits (the cubit being a cubit and a hand width): the base shall be a cubit and the width a cubit, and its border on its border's edge all around one span; and this shall be the height of the base of the altar.

an ancient unit of length that had several definitions according to each of the various different cultures that used the unit

The cubit is an ancient unit of length that had several definitions according to each of the various different cultures that used the unit.

a measurement from the tip of the elbow to the tip of the middle finger

According to the Hebrews a cubit is a measurement from the tip of the elbow to the tip of the middle finger.

a unit of measurement 18 inches long

So, for anyone's general reference, a cubit is a unit of measurement 18 inches long.

an ancient linear measurement

Twenty cubits (the cubit, an ancient linear measurement, is equal to roughly 19 inches) is the maximum allowed by Jewish law.

an ancient unit of length that may have originated in Egypt close to 5,000 years ago

The cubit is an ancient unit of length that may have originated in Egypt close to 5,000 years ago.

the length of the human forearm

2The cubit was originally the length of the human forearm.

a measurement of roughly 18 inches by measuring of the forearm

Cubit is a measurement of roughly 18 inches by measuring of the forearm.

about 18 inches or 45 centimetres in length

A cubit was about 18 inches or 45 centimetres in length.

about 18 inches, or the length from our elbow to the tip of our fingers

A cubit is about 18 inches, or the length from our elbow to the tip of our fingers, so the Ark was 450 feet long, 75 feet wide and 45 feet high.

an ancient unit of length primarily associated with the Sumerians, Egyptians and Israelites

The cubit is an ancient unit of length primarily associated with the Sumerians, Egyptians and Israelites.

a term of measurement, about a foot-and-a-half

A cubit is a term of measurement, about a foot-and-a-half.

the length of a man's arm (generally measured as 18 inches)

A cubit is the length of a man's arm (generally measured as 18 inches), and a span is the widest extent that a man can spread the palm and fingers of Gath's hand (generally measured as 1/2 of a cubit, or 9 inches).

unit of length

Second: Sumerian cubit (cbt) is unit of length.

about 18 inches or the length from a man’s elbow to Ark's fingertips

A cubit is about 18 inches or the length from a man’s elbow to Ark's fingertips.