I have started using Geometry Node in 2.92 and 2.93A.
I needed to figure out how to increase size of particle in only Z-axis.
Appears there’s only “rotation” and “position” has vector … and scale is only supported as “float”.
Is this so ?

Is there any way I can justincrease “scale size” along z-axis only for a particle in a geometry?

Scale is definitely a vector under the hood. Blender is smart enough to convert/cast between float and vectors for you. To see for yourself add an attribute random node and change it to float type. All of the random scale values will be uniform on the xyz axis, so basically if the scale float is say 2, then it gets converted to (2,2,2). If you change the random type to be vector and put in different random max values, you will will see the instances scale non-uniformly.

If you want to increase instances scale along only the z axis, just use the attribute vector math in multiply mode and put in the added vector as (0,0, 2) if you wanted to double the scale on the z axis. You could also use this node in add or subtract mode etc, depending on what you are trying to do.