Lambda is the eleventh letter of the Greek alphabet, representing the voiced alveolar lateral approximant IPA: [l]. In the system of Greek numerals, lambda has a value of 30. Lambda is derived from the Phoenician Lamed. Lambda gave rise to the Latin L and the Cyrillic El (Л). The ancient grammarians and dramatists give evidence to the pronunciation as (λάβδα) in Classical Greek times. In Modern Greek, the name of the letter, Λάμδα, is pronounced.

The Phoenician alphabet is a consonantal alphabet used across the Mediterranean civilization of Phoenicia for most of the 1st millennium BCE. It was the first mature alphabet, and attested in Canaanite and Aramaic inscriptions found across the Mediterranean region. In the history of writing systems, the Phoenician script also marked the first to have a fixed writing direction—while previous systems were multi-directional, Phoenician was written horizontally, from right to left. It developed directly from the Proto-Sinaitic script used during the Late Bronze Age, which was derived in turn from Egyptian hieroglyphs.