(US) A letter mailed at a post office and either kept for general delivery, or delivered to a post office box, at that same post office.

(humorous) To watch something that has virtually no movement, hence, something very boring.

(exobiology) A formula for calculating the probability of civilizations existing elsewhere in the Milky Way galaxy and of their ability to communicate with Earth.

(informal, idiomatic) Without any hesitation; instantly.

A psychoactive drug taken deliberately for the effect it has on the mind rather than for its medicinal effects.

You can show someone how to do something, but you can't make them do it.

Understanding is reached; one comprehends.

One who is drafted (into a military service, etc).

Without water or moisture, said of something that has previously been wet or moist; resulting from the process of drying. / Usually of foods: cured, preserved by drying. / Sold raw and unprocessed.

simple past tense and past participle of dry