Scientists use very specific terms to describe science topics, because science is detailed, analytical, and also very specific.
BIOLOGY: genus/species
CHEMISTRY: formulas, structures, registry numbers, chemical names
GEOLOGY/GEOGRAPHY: Names rock formation, latitude and longitude, crystal structures
MEDICINE: Disease names, specifically named body parts and functions, drug names, bacterial and viral identifications
We don't often think about indexing, but it can be helpful to understand how indexing works in order to search effectively.
And algorithm is used to tell the computer HOW the keywords should be searched. The algorithm can be simple or complex. It is also often proprietary, and a closely held secret.
The basic elements of an algorithm are Boolean Operators. Those are : AND OR NOT