This is the 302nd most frequent Thai word.
เด
The Thai word "เด" is an informal particle used to soften or emphasize commands, requests, or statements.
Here, 'เด' acts as an informal particle to emphasize or add a colloquial tone to the statement.
เขาดูมีความสุขจริงเด.
He seems truly happy, 'de'.
This usage of 'เด' is as a name for the cat, not implying any grammatical or semantic meaning.
เมื่อวานนี้ เราพบแมวเด.
Yesterday, we met the cat named 'De'.
This 'เด' is used as a demonstrative, indicating that the mentioned shirt on the table is being referred to.