What it means
Lakshmi's seed syllable, shreem, repeated. There's no sentence here, only sound.
Where it comes from
In the tantric and Shrividya traditions, seed syllables are sometimes chanted on their own. The idea is to stop reaching for meaning and let the mind rest on sound alone. It takes some practice, so newcomers are usually pointed to the full mantra, Om Shreem Mahalakshmyai Namah, first.
How to chant it
A quiet place and a straight back. Pronunciation matters, so learn it from someone who knows.
When: Fridays, morning or evening.
Try it now
The japa counter opens with this mantra selected and keeps count for you.