阝 is the component form of two distinct radicals found either on the left or right of a character. It is the component form of 阜 when used on the left of a character, as in 阮, and the component form of 邑 when used on the right of a character, as in 邧.
Also known as 雙耳旁/双耳旁 (shuāng'ěrpáng) (shuāng'ěrpáng) or 雙耳刀/双耳刀 (shuāng'ěrdāo) (shuāng'ěrdāo) when referring to the radical written on either side of a character.