From BiblePortal Wikipedia

Plumb-Line [1]

( אֲנָךְ , Ansk, A Plummet) or Plummet ( מַשְׁקֵלֶת , Mishkileth,  Isaiah 28:17, or מַשְׁקֹלֶת , Mishkoleth. Ma Weight). Amos says ( Amos 7:7), "Behold, the Lord stood upon a wall, made by a plumb-line, with a plumb-line in his hand;" and in the threatenings denounced against Jerusalem for the idolatries of Manasseh, we read, "I will stretch over Jerusalem the line of Samaria, and the plummet of the house of Ahab" ( 2 Kings 21:13). In  Zechariah 4:10, the original term for the plumb-bob is אֶבֶן בְּדַיל , Eben Bedil, Stone Of Tin. The use of the plumb line in the measurement of superficial areas was early known to the Egyptians, and is ascribed to their king Menes. (See Handicraft).