Patent websites vary in coverage. Some only have full text or images for recent years. Some have better quality images than others. In some search engines, keywords only work on recent years. If you are doing a full, deep, and serious search, be sure to identify and search on the patent classifications (see details on the Patents Guide) as well as keywords.
There are three types of U.S. patents:
1) Utility patents may be granted to anyone who invents or discovers any new and useful process, machine, article of manufacture, or composition of matter, or any new and useful improvement thereof;
2) Design patents may be granted to anyone who invents a new, original, and ornamental design for an article of manufacture; and
3) Plant patents may be granted to anyone who invents or discovers and asexually reproduces any distinct and new variety of plant.
(from USPTO website)
... and patents include definitions of terms used. Remember, though, that patents are written by attorneys and not by engineers!
This pages offers links to various tools including:
Through UF subscription (use UF VPN to access when off-campus):
Free View/Read Access Online:
Remember: most government standards are also free, such as NASA standards.