וַיַּ֡רְא יוֹשֵׁב֩ הָאָ֨רֶץ הַֽכְּנַעֲנִ֜י אֶת־הָאֵ֗בֶל בְּגֹ֙רֶן֙ הָֽאָטָ֔ד וַיֹּ֣אמְר֔וּ אֵֽבֶל־כָּבֵ֥ד זֶ֖ה לְמִצְרָ֑יִם עַל־כֵּ֞ן קָרָ֤א שְׁמָהּ֙ אָבֵ֣ל מִצְרַ֔יִם אֲשֶׁ֖ר בְּעֵ֥בֶר הַיַּרְדֵּֽן׃
And when the inhabitants of the land, the Canaanites, saw the mourning in the floor of Atad, they said: ‘This is a grievous amourning to the Egyptians.’ Wherefore the name of it was called Abel-mizraim, which is beyond the Jordan.
Read kabbalistic (mystical) interpretation of Genesis 50:11: and classical mystical sources.