Frequency List
A word list sorted by how often each word appears in real speech and writing, most common first.
A frequency list ranks words by how often they occur in a corpus, a large collection of real texts and transcribed speech. The most useful property of such lists is how top-heavy they are: in English, the top 100 words cover about half of everything, and the top 1000 cover roughly 85% of everyday conversation.
For learners, a frequency list is a prioritization tool. It answers "which words first?" with data instead of a textbook editor's theme choices. Lists differ slightly depending on the corpus used, spoken vs written, British vs American, but the top 1000 are remarkably stable across all of them.