What do you call words such as “the, an, a, to, and”?
Solution 1:
According to the ones you shared in your example:
- the, an,a = articles.
- and = additive coordinating conjunction.
- to = preposition.
I guess you could use just "Common Words" or "Stop Words", that's usually among the technical jargons that are stated while reading about indexing operations in Search Engines.
e.g., http://lucene.apache.org/core/3_0_3/api/core/org/apache/lucene/analysis/package-summary.html#Tokenization
Cheers.