I think the partial pass used to apply under the CAA exam system wherby you had 2 initially sittings... (so called Nav's and Tech's), 14 in total.
If you passed 7 or more out of the combined two sittings, this was termed "partial pass" and you could then go on to take the remaining re-takes to gain a full pass. If you passed less than 7 initially, then you started again and negated any passes you had.
Partial pass has been abolished under JAR