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Definitions

foundational

[foun-dey-shuh-nl] / faʊnˈdeɪ ʃə nl /
ADJECTIVE
bottom
Synonyms
STRONG
base basement basic ground last primary radical underlying
WEAK
basal lowermost lowest meat-and-potatoes nethermost rock-bottom undermost
Antonyms
STRONG
secondary
WEAK
highest top
ADJECTIVE
elementary
Synonyms
STRONGEST
elemental fundamental rudimentary straightforward underlying
WEAK
ABCs abecedarian basal beginning child's play clear duck soup easy essential facile initial introductory meat and potatoes original plain prefatory preliminary primary primitive primo simplest simplex simplified substratal uncomplex uncomplicated
Antonyms
STRONGEST
additional advanced extra secondary
WEAK
abstruse complex complicated compound difficult hard intricate involved
ADJECTIVE
fundamental
Synonyms
STRONGEST
central constitutional crucial elemental elementary essential indispensable integral intrinsic major necessary paramount principal radical significant structural theoretical underlying vital
STRONG
bottom cardinal first key organic original primary prime primitive requisite supporting
WEAK
axiological axiomatic basal bottom-line constitutive grassroots meat-and-potatoes primordial rudimentary substratal substrative sustaining underived
Antonyms
STRONGEST
accessory auxiliary extrinsic inessential insignificant learned least lesser minor needless nonessential secondary trivial unimportant unnecessary
WEAK
additional advanced extra subordinate
ADJECTIVE
lowermost
Synonyms
WEAK
basal base basement basic ground last lowest meat-and-potatoes nethermost primary radical rock-bottom underlying undermost
ADJECTIVE
nethermost
Synonyms
WEAK
basal base basement basic deepest ground last lowermost lowest meat-and-potatoes primary radical rock-bottom underlying undermost
ADJECTIVE
primary/prime
Synonyms
WEAK
basal beginning bottom central elemental elementary essential first introductory meat-and-potatoes original primitive principal radical rudimentary simple three R's ultimate underivative underived underlying
Antonyms
WEAK
auxiliary latest least minor secondary supplemental
ADJECTIVE
radical
Synonyms
STRONGEST
profound
STRONG
basal bottom cardinal constitutional essential native natural organic original primary primitive
WEAK
deep-seated inherent innate intrinsic meat-and-potatoes primal thoroughgoing underlying vital
Antonyms
STRONG
inessential minor secondary unimportant
WEAK
extrinsic nonessential superficial
ADJECTIVE
rudimental
Synonyms
WEAK
ABCs abecedarian basal basic beginning child's play clear duck soup easy elemental essential facile fundamental initial introductory meat and potatoes original plain prefatory preliminary primary primitive primo rudimentary simplest simplex simplified straightforward substratal uncomplex uncomplicated underlying
ADJECTIVE
undermost
Synonyms
WEAK
basal base basement basic ground last lowermost lowest meat-and-potatoes nethermost primary radical rock-bottom underlying

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

SpaceX merged with xAI in February, accelerating Musk’s plans to turn SpaceX into an AI giant capable of running data centers and developing foundational AI models and applications.

From Barron's • Apr. 7, 2026

China’s “microelectronics, their motors, their rare earth, their magnets—which is foundational to robotics—they are the world’s best,” Huang said in a podcast in March.

From The Wall Street Journal • Apr. 3, 2026

Donald Trump’s executive order to promote AI in schools argued that the tech “sparks curiosity and creativity” and “will equip our students with the foundational knowledge and skills.”

From Salon • Mar. 30, 2026

The researchers see it as a foundational design that could eventually be developed into practical tools for clinical and laboratory use.

From Science Daily • Mar. 25, 2026

“We would forfeit the protection afforded by the foundational covenants of the treaty.”

From "Fablehaven" by Brandon Mull