thesaurus(A compilation of terms showing synonyms, related terms and other relationships and dependencies, often used in a book format or as a standardized, controlled vocabulary for an information storage and retrieval system)
thesis(A dissertation on a particular subject, in which original research has been done, usually by a candidate for a diploma or degree, or a proposition put forward for consideration, to be discussed and proved or maintained against objections)
thickening(Any process beyond gravity sedimentation that increases the concentration of solids in sludge with or without the use of chemical flocculants)