The modifier letter double apostrophe (ˮ) is a spacing glyph. It is used in the orthography of Tundra Nenets to denote a glottal stop, or in the orthography of Dan to indicate that a syllable has a top tone. It is encoded at U+02EE ˮ Modifier letter double apostrophe (HTML ˮ).
References
Modifier letter double apostrophe Wikipedia(Text) CC BY-SA