Period
Part of speech: adjective
Definition: Appropriate for a given historical era.
Part of speech: interjection
Definition: And nothing else; and nothing less; used for emphasis.
Part of speech: noun
Definition: Punctuation mark “” (indicating the ending of a sentence or marking an abbreviation). A length of time. An epoch, era, time in history or in a person's life. A specific length of time that an activity (such as a game or a school day) is conventionally divided into. The minimum interval during which the same characteristics of a periodic phenomenon recur, such as the repetition of a wave or the rotation of a planet. Female menstruation. A row in the periodic table of the elements. A Drosophila gene which gene product is involved in regulation of the circadian rhythm
Example sentence: If the human race wishes to have a prolonged and indefinite period of material prosperity, they have only got to behave in a peaceful and helpful way toward one another.
Menstruation
Part of speech: noun
Definition: The periodic discharging of the menses, the flow of blood and cells from the lining of the uterus in females of humans and other primates.