Meaning

noun a diacritical mark (,) placed below the letter c to indicate that it is pronounced as an s

originBorrowed from Spanish cedilla (literally “little zed”), c. 1600. In Spanish cedilla referred to the letter ⟨Ç⟩, which had evolved from ⟨Ꝣ⟩, a Visigothic form of the letter Z (called a Z with copete); hence the name. The lower part of ⟨Ç⟩ (which came to be reinterpreted as a diacritical mark under a C) is the remnant of the original Z, after it gradually reduced in size; whereas the upper part was…

Etymology from Wiktionary, CC BY-SA 3.0