HCL may refer to:
==Science and medicine== Hairy cell leukemia, an uncommon and slowly progressing B cell leukemia Harvard Cyclotron Laboratory, from 1961 to 2002, a proton accelerator used for research and development Hollow-cathode lamp, a spectral line source used in physics and chemistry Hydrochloric acid, a solution of hydrogen chloride in water Hydrochloride, the salt of hydrochloric acid and an organic base Hydrogen chloride, chemical formula HCl Hypomania Checklist, a questionnaire used to screen for hypomania and bipolar spectrum disorders HCL color space, a color space model designed to accord with human perception of color
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).