A job in IMPLAN = the annual average of monthly jobs in that industry (this is the same definition used by QCEW, BLS, and BEA nationally). Thus, 1 job lasting 12 months = 2 jobs lasting 6 months each = 3 jobs lasting 4 months each. A job can be either full-time or part-time.
Information on converting between IMPLAN jobs and Full-Time Equivalents can be found in the 536 FTE & Employee Compensation Conversion Tables found in our downloads section (link below).
Please note also that Full-Time Equivalent by BLS definitions is 35+ hours.
BLS also has this definition in their Glossary, but definitions depend on the survey (notice the two definitions of Full-time)