| Subclass T | Technology (General) |
| Subclass TA | Engineering (General). Civil engineering |
| Subclass TC | Hydraulic engineering. Ocean engineering |
| Subclass TD | Environmental technology. Sanitary engineering |
| Subclass TE | Highway engineering. Roads and pavements |
| Subclass TF | Railroad engineering and operation |
| Subclass TG | Bridge engineering |
| Subclass TH | Building construction |
| Subclass TJ | Mechanical engineering and machinery |
| Subclass TK | Electrical engineering. Electronics. Nuclear engineering |
| Subclass TL | Motor vehicles. Aeronautics. Astronautics |
| Subclass TN | Mining engineering. Metallurgy |
| Subclass TP | Chemical technology |
| Subclass TR | Photography |
| Subclass TS | Manufactures |
| Subclass TT | Handicrafts. Arts and crafts |
| Subclass TX | Home economics |
https://www.loc.gov/aba/cataloging/classification/lcco/lcco_t.pdf