adj

• (linguistics) Made with a somewhat elevated position of some certain part of the tongue, in relation to the palate; midway between the high and the low; said of certain vowel sounds, such as, [e o ɛ ɔ].
• (originally African-American Vernacular and Internet slang) Mediocre; of middling quality.
  "The song is one of his best, but its real power comes from the accompanying, highly-stylized video wherein Lil Nas X breaks out of a prison populated with Black gay men (and, for an unspecified reason, Jack Harlow in an unseemly role as the Straight White Savior who delivers a verse that is mid at best and inappropriate at worst)."
• (Internet slang, by extension) Trashy; low-quality.

noun

• (location, online gaming, slang) The middle of the battlefield.
  "We need to retake mid."

adv

• (location, online gaming, slang) To or into the middle of the battlefield.
  "Everyone head mid."

prep

• (archaic) Amid.
  "mid the best"