Common words:
* semicolon: a punctuation mark (;)
* semifinal: a round in a competition before the final
* semi-trailer: a type of truck with a trailer attached
* semiannual: happening twice a year
* semiformal: a dress code that is more formal than casual but less formal than formal
* semimonthly: happening twice a month
* semiautomatic: a firearm that requires a separate action for each shot
Less common words:
* semicircle: half a circle
* semiotics: the study of signs and symbols
* semibreve: a musical note that lasts for four beats
* semiopaque: partly opaque
* semidetached: a house attached to another house on one side
* semifluid: a substance that has some properties of a liquid and some properties of a solid
* semiprofessional: a person who is paid for their work but does not do it full-time
Informal words:
* semi-pro: a semiprofessional person
* semi-naked: partially clothed
Technical words:
* semimolar: a unit of concentration
* semimetal: a substance with properties of both metals and nonmetals
* semivowel: a consonant that sounds like a vowel
* semiquinone: a chemical radical
This list provides a variety of words starting with "semi," showcasing its diverse usage in the English language.