LDA may refer to: Aviation Localizer type directional aid, an instrument approach to an airport Landing distance available, the length of runway that is available for the ground run of an airplane landing Law Legal document assistant, a non-lawyer authorized to assist with the preparation of legal instruments Lobbying Disclosure Act of 1995, legislation in the United States Legal drinking age, the minimum age at which one can legally consume alcohol Medicine Left-displaced abomasum, condition of ruminants Low dose allergens, a variant of enzyme potentiated desensitization Science and technology Laser Doppler anemometry, technique to measure velocity Latent Dirichlet allocation, a generative statistical model Linear diode array, used for digitizing x-ray images Linear discriminant analysis, a type of statistical analysis Lithium diisopropylamide, a strong base in chemistry Local delivery agent, software that delivers e-mail messages Local-density approximation, in quantum-mechanical density functional theory Low density amorphous ice, an amorphous solid form of water Lobate debris apron, a type of geologic feature observed on Mars Organizations Lahore Development Authority, agency in Lahore, Pakistan Liga Deportiva Alajuelense, a Costa Rican football club London Democratic Association, 19th century organisation in England London Development Agency, regional development agency for the London region in England Lord's Day Alliance, an ecumenical Christian first-day Sabbatarian organization Other uses LDA (singer) Little Dark Age, a 2018 studio album by MGMT