Petit point is a style of needlepoint not often used nowadays. But really, it's not too dissimilar to cross stitch, and it can be useful for many reasons!
Common Cross Stitch Terms
Petit Point - Similar But Different to Cross Stitch and Smaller! ⋆
How To Do Petit Point Or Half-Cross Stitch – Soltan Art Studio
Petit Point. What Is It? – Natalia's Fine Needlework
What's The Difference Between Needlepoint And Petit Point? - Wayne Arthur Gallery
Common Cross Stitch Terms
What is the difference between cross stitch and petit point? - CraftTribeOnline.com
Kathrin's Blog: Cross stitch vs. Petit point
Petit Point vs Cross Stitch (Similarities and Differences) - Gathering Thread
Ultimate Guide to Fractional Stitches for Cross Stitch