We have here one of the finest Oham features.
What does "centering" mean?
Centering means to fix which is the group or part -of the eight Oham groups or parts- a given word belongs to.
This can be achieved either in a general centering way or in a specific centering way.
What is general centering?
Let us suppose the word מַחְשׁב, computer.
Doing a general centering of this word means this: מַחְשֵׁב is a word P-t type.
Such an answer is not a full answer. It is an answer that requires a further search from the part of the fellow who put the question. But this answer discards and banishes all other possibilities and is saying three things:
1. The root of this word is a three letter root and it is חשב
2. Letter מ is a prefix
3. The explanation on the pattern structure and meaning this word belongs to has to be first sought and then looked at the Index P-t