What is word stemming?
Word stemming is the process that normalizes the tense and the plurality of words for searching, in order to cast a wider net and return potentially more relevant results.
For example, searching for "helping" will display results for "help," "helped," or "helps" as seen below:
What are stop words?
Stop words are commonly used words like "the," "and," "a," "them," etc. Stop words are considered irrelevant for searching purposes because of how frequently they appear in the English language, and since the majority of stop words don't have much contextual meaning. The removal of stop words from the indexing and searching process increases the indexing and searching speed and improves search ranking by focusing on keywords/terms.
An example would be how searching for "the deer" vs "deer" would yield similar results (as per user expectations.) The list of words that are excluded in this way is known as a "stop list".
Goldfynch's search engine employs word stemming. Additionally, as part of the indexing process, Goldfynch removes stop words. This happens both when indexing entries for searching and when retrieving them as a result of the search query.