Gershayim between the penultimate and last letters ( ״ e.g. פזצט״א) marks acronyms, alphabetic numerals, names of Hebrew letters, linguistic roots and, in older texts, transcriptions of foreign words. Placed above a letter ( ֞ e.g. פְּרִ֞י) it is one of the cantillation marks.
Read more about this topic: Hebrew Diacritics