Hmmm.  Good question.

Do you remember the show "Incredible Hulk"? Where the nerdy guy changes into this hug hulking beast?  That's a morph.

In Poser, it's something (not sure if it's a tool or a bit of coding) that allows you to change the shape of the basic figure. For example you can increase or decrease the size of the chest/bust, various muscles; change face expressions etc.  All of those changes = "morphs."

Hope that helps.

"It is good to see ourselves as others see us. Try as we may, we are never
able to know ourselves fully as we are, especially the evil side of us.
This we can do only if we are not angry with our critics but will take in good
heart whatever they might have to say." - Ghandi