Term Frequency

The number of occurrences of a word $w$ in a document $d$.

The normalized term frequency is divided by the size of the document $d$. $\mathrm{tf}(w,d)=\frac{n}{\mid d\mid }$ where $n$ is the number of occurrences of $w$ in $d$.

They are induced by adding up one hot Word Embeddings, see TF-IDF Word Embedding

Also see Inverse Document Frequency.