Update "Beg" to Beginning on IACV definition

Why is this change being made?

I was confused about what "Beg" was and then realized it was beginning

Does this MR meet the acceptance criteria?

Assign to DRI

• Did you assign this change to the correct DRI of the page or information you are changing?

Conformity

• Added description to this MR explaining the reasons for the proposed change, per say-why-not-just-what