English Reference
Adjective

theoretical

adj.
C1 Advanced Oxford US /ˌθiɝˈɛtɪkəɫ/ UK /θiəɹˈɛtɪkəl/ the·o·ret·i·cal

adj.based on ideas or possibilities rather than on real things you can see or touch. You use this when something is possible in your mind but has not happened in real life yet.

adj.relating to or based on a system of ideas rather than practical application. Often used to describe a scenario that is hypothetical or speculative in nature.


SIMPLE

The plan is still theoretical and hasn't been tested.

CONTEXTUAL

While the solution works in a theoretical sense, the engineers are worried about how it will perform in extreme weather.

COMPLEX

The physicist presented a theoretical model of the universe that challenged existing laws, though empirical evidence to support his claims remains elusive due to current technological limitations.

Usage

Commonly used in contrast with 'practical' or 'applied'.

Usage theoretical physicist · theoretical calculations · theoretical predictions

They faced fines, or in extreme cases the theoretical possibility of three months in prison, depending on the reasons provided for the absences.

The Guardian· 15 Aug 2026

The Iranian attack on US forces near al-Tanf, southern Syria, in July demonstrated that Iran’s use of force inside Syrian territory is no longer just a theoretical possibility.

Al Jazeera· 15 Aug 2026

Common in science writing


From Middle English theorothycall, probably from Latin theōrēticus + -al, from Ancient Greek θεωρητικός (theōrētikós).

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

This entry
Origin Latin theōrēticus
Level C1 · Advanced
Frequency Common
Updated