and co.
CO
noun
uk /ˌsiːˈəʊ/ us /ˌsiːˈoʊ/

COnoun (MILITARY)

[ C ]
abbreviation for Commanding Officer: a person in charge of a military unit指挥官；司令（Commanding Office的缩写）

SMART Vocabulary: related words and phrases

General ranks in the armed forces
ADC
adjutant
adjutant general
aide-de-camp
artificer
bombardier
captain
CINC
commandant
commander-in-chief
commissioned
commissioned officer
grunt
lieutenant
Lt
marshal
NCO
non-commissioned
non-commissioned officer
warrant officer

COnoun (ADDRESS)

written abbreviation for the US state of Colorado: used in addresses（美国）科罗拉多州（写地址时Colorado的缩写）

SMART Vocabulary: related words and phrases

Towns & regions: named regions of countries
Aberdeen City
Aberdeenshire
Affrilachian
AK
AL
East Yorkshire
English Canadian
Essex
fife
Minnesotan
Mississippi
Mississippian
Missouri
Missourian
South Glamorgan
South Lanarkshire
Staffordshire
Stirling
Stirlingshire
the Fertile Crescent

co- | American Dictionary

co-
prefix
us/koʊ/
together; with:
co-author
co-founder
They were named co-winners of the player of the week award.
Co.
noun[ U ]
us/ˈkʌm·pə·ni, koʊ/
abbreviation for company :
Doubleday & Co., publishers

co- | Business English

co-
prefix
uk /kəʊ-/us
together, or with someone else; used to form verbs:
co-direct/co-found/co-manage
along with someone else; used to form nouns:
co-chairman/co-director/co-manager
co-ownership
Co.
noun[ U ]
ukus
abbreviation for company:
Ford Motor Co.
Tiffany & Co.