l is the twelfth letter of the english alphabet, and a vocal consonant. it is usually called a semivowel or liquid. its form and value are from the greek, through the latin, the form of the greek letter being from the phoenician, and the ultimate origin prob. egyptian. etymologically, it is most closely related to r and u; as in pilgrim, peregrine, couch (fr. collocare), aubura (fr. ll. alburnus).-as a numeral, l stands for fifty in the english, as in the latin language.-an extension at right angles to the length of a main building, giving to the ground plan a form resembling the letter l; sometimes less properly applied to a narrower, or lower, extension in the direction of the length of the main building; a wing.-a short right-angled pipe fitting, used in connecting two pipes at right angles.