biological

adjective

bi·​o·​log·​i·​cal ˌbī-ə-ˈlä-ji-kəl 

variants or less commonly biologic

ˌbī-ə-ˈlä-jik 

1

: of or relating to biology or to life and living processes

2

: used in or produced by applied biology

3

: connected by direct genetic relationship rather than by adoption or marriage

her biological father

biologically

ˌbī-ə-ˈlä-ji-k(ə-)lē 

adverb

Synonyms of biological

• birth
• natural
• legitimate

Examples of biological in a Sentence

the rights of the biological father in this case

Recent Examples on the Web

The policy meant the top biological female finishers were designated co-champions, leading to widespread images of Hernandez sharing the top step of the medal podium with female athletes. —Alejandro Avila Outkick, FOXNews.com, 19 May 2026

The researchers used this to look at the relationship between sleep duration and the individuals’ biological ages, which use different biomarkers from different organ systems to track aging. —Alex Knapp, Forbes.com, 18 May 2026

Martinez-Armstrong picked the boy up from the boy’s biological mother several days before the fatal incident, according to the man’s arrest affidavit. —Lauren Penington, Denver Post, 18 May 2026

For heavier infestations, Bacillus thuringiensis is an effective and organic-approved biological treatment. —Rae Ford, Martha Stewart, 17 May 2026

Word History

First Known Use

1818, in the meaning defined at sense 1

Phrases Containing biological

• biological clock
• biological control
• biological oxygen demand
• biological parent
• biological warfare
• biological weapon
• non-biological

Rhymes for biological

• illogical
• zoological
• aetiological
• anthropological
• archaeological
• archeological
• axiological
• climatological
• deontological
• dermatological
• eschatological
• etiological

Kids Definition

biological

adjective

bi·​o·​log·​i·​cal

ˌbī-ə-ˈläj-i-kəl

variants also biologic

-ˈläj-ik

1

: of or relating to biology or to life and living things

2

: connected by a relationship involving heredity rather than by one involving adoption or marriage

his biological father

biologically

-ˈläj-i-k(ə-)lē

adverb

Medical Definition

biological

adjective

variants also biologic

1

: of or relating to biology or to life and living processes

2

: used in or produced by applied biology

3

: related by direct genetic relationship rather than by adoption or marriage

an adoptee who searched for years for her biological parents

biologically

-i-k(ə-)lē 

adverb