In ABET accreditation criteria, what is the meaning of "one year of X"?
ABET formally defines a "year" as


  The lesser of 32 semester-hours (or equivalent) or one-fourth of the credits required for graduation [1].


The wiggle room in the definition is almost certainly because of the wide variety of credit systems used by various schools. "One and a third years" would then equate either to 42 semester hours, or four full trimesters or quarters of study for those on alternate study schedules.

[1] http://www.abet.org/eac-criteria-2014-2015/