Ancient Roman libra (translated as "pound"), a weight measure with derivative units denoted with "L" or a derived character:
Pound (currency), a number of currencies from the British Empire, abbreviated £ or (historically) "l", "L", or "". (Some fonts use a two-bar version resembling the lira sign ₤.)
Livre (disambiguation), a number of currencies from the French Empire, with the original abbreviated "£", "₶", or "lt"
Lira, a number of currencies from Italy and the Ottoman Empire, abbreviated as ₤
Leaf (books) ("l." or ℓ), an alternate numbering for books, in contrast to "p." for pages
Specification for a line of text, for example "l. 3" is the third line of text
Scienceedit
Mathematicsedit
L, constructible universe, a particular class of sets which can be described entirely in terms of simpler sets