# Stem

### Description
Extracts the stem (available for various languages) from all strings in a `[OBJ,STRING]` input.
Strings are expected to be single words (see `Tokenize` block).

### Input
- `SOURCE [OBJ,STRING]`: a 2-column input with an object-string pair. Typically obtained with the `Extract string` and `Tokenize` blocks.

### Output
- `RESULT [OBJ,STRING]`: the pairs from `SOURCE`, where the string has been modified
- `STRINGS [STRING]`: the modified strings, without the object they were paired to

### Parameters
- `Stemming`: strings (single words) can be stemmed for a specific language or left as they are

Output scores can be [aggregated](docs://score_aggregation) and/or [normalised](docs://score_normalisation).