A job in IMPLAN = the annual average of monthly jobs in that industry (this is the same definition used by the BLS and BEA). 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. Similarly, a job that lasts one quarter of the year would be 0.25 jobs. Note that a person can hold more than one job, so the job count is not necessarily the same as the count of employed persons.
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. Download 2017 Version
Find other conversion tables here: https://implanhelp.zendesk.com/hc/en-us/articles/115002997573-536-Sectoring-Scheme
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)