陸 is the most common Chinese surname character that romanizes as Lou.

The meaning of 陸 is land or shore.

This may not be the character you want as Lou can represent various characters/surnames like 盧 (a type of rice vessel), 樓 (tower), 婁 (astrological mansion), or 路 (road).

Other variations of romanization include: Lau, Lo, Lu, Liu, Loo, and Low.

ルー is the name Lou in Japanese.

Note: Because this title is entirely Japanese Katakana, it should be written by a Japanese calligrapher.

This is a common Mandarin Chinese transliteration for the female French name Lou.

瑪麗璐 is the name Mary-Lou in Chinese (Mandarin).

メアリールー is the name Mary-Lou in Japanese (Katakana).

Note: Because this title is entirely Japanese Katakana, it should be written by a Japanese calligrapher.

劉 is one of the most common Cantonese-Chinese surnames, often associated with the Han Dynasty, meaning "to kill" or "flow," or related to a battle-ax.

There are other characters that can be surnames which romanize as Lau from Cantonese:
柳 (Liǔ): Meaning "willow".
婁 (Lóu): Related to lunar mansions.
勞 (Láo) / 老 (Lǎo): Less common variants.
Note the romanization in the () is romanization from Mandarin. 劉 are surnames in many Chinese dialects but pronunciation and romanization varies.