Intra is defined as within.
An example of intra used as a prefix is in the word "intrapersonal," which means a person's relationship with him or herself.
within, inside: intramural, intravenous
Origin of intra-Classical Latin intra- from tra, within, inside from an unverified form intera, akin to interior, inter: see inter-
Origin of intra-Latin intrā- from intrā ; see en in Indo-European roots.