They shall become one flesh
Figuratively: they merged, they became a pair.
("Therefore a man shall leave his father and mother and be joined to his wife, and they shall become one flesh" - Genesis 2:1)
Translation
Expression (Hebrew)
וְהָיוּ לְבָשָׂר אֶחָד, הָיוּ לְבָשָׂר אֶחָד
Definition (Hebrew)
בִּמְלִיצָה: הִתְמַזְּגוּ.הָפְכוּ לְזוּג.
("עַל כֵּן יַעֲזָב אִישׁ אֶת אָבִיו וְאֶת אִמּוֹ וְדָבַק בְּאִשְׁתּוֹ וְהָיוּ לְבָשָׂר אֶחָד"- בְּרֵאשִׁית ב כַּד)