Could mean either that 3/5 of baby's head is free, or 3/5 of the head is engaged.
Different midwives do it differently.
My midwife writes palp next to it. So for example she wrote in mine that I was 2/5 palpable which means she can feel 2/5 of baby's head still free, so 3/5 was engaged.
I'd ask her next time you see her.
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