魔，梵文 Mara, 魔羅，此雲殺者，能殺害眾生，法身慧命故。漢語的魔之一字，來自佛經，來自梵文，為魔羅的簡稱。如下：

魔，漢語常用字（一級字） [1]  ，讀作mó，最早見於《說文》小篆，是隨着南北朝佛經譯文開始產生的 [2]  。本義為梵語魔羅的簡稱；引申泛指惡魔，怪物；又引申為邪惡的人或勢力；妖魔容易引起人們好奇，所以又引申指神奇的、對某事物愛好入迷等 [3]  。

魔有四種，無非都是干擾修行令不入正道的四種因素。但魔由心生，因心外無法。故，干擾起時，唯一心內觀即可。

The word Māra comes from the Sanskrit form of the verbal root mṛ. It takes a present indicative form mṛyate and a causative form mārayati (with strengthening of the root vowel from ṛ to ār). Māra is a verbal noun from the causative root and means 'causing death' or 'killing'.^[4] It is related to other words for death from the same root, such as: maraṇa and mṛtyu. The latter is a name for death personified and is sometimes identified with Yama.

The root mṛ is related to the Indo-European verbal root *mer meaning "die, disappear" in the context of "death, murder or destruction". It is "very wide-spread" in Indo-European languages suggesting it to be of great antiquity, according to Mallory and Adams.^[5]