These are function words and high-frequency nouns/verbs.
5,000+ words. The Oxford 5000 adds an extra 2,000 words for academic and complex professional topics. 2. Frequency vs. Utility: The "Core" Words 5000 most common english words list
Knowing the 5,000 most common English words is a massive milestone; it typically allows you to understand approximately 99% of most everyday texts These are function words and high-frequency nouns/verbs