fundamentally

Fundamentally is an adverb used to indicate that a statement concerns the essential nature or underlying basis of something. It signals that a claim goes beyond superficial characteristics to address core principles, causes, or structures. In everyday language it is often synonymous with essentially or basically, but it tends to carry a stronger emphasis on the most important, irreducible aspects of a subject.

The term derives from the adjective fundamental, which itself comes from Medieval Latin fundamentalis (from fundamentum, “foundation”). English formed the adverb by adding the suffix -ly, with attestations appearing in the 15th century and becoming common in later centuries.

In discourse, fundamentally is used to reframe discussion around the underlying issue rather than incidental details. For example, one might say that two proposals are fundamentally different, or that a theory is fundamentally flawed because it fails to account for a basic premise. In science and philosophy, it often introduces claims about essential properties or laws that govern a system.

Related terms include fundamental and essentially; the word is commonly contrasted with more surface-oriented descriptors such as superficial or incidental.