underlying
underlying — adjective
1. Describes a cause, reason, feeling, or quality that is real and produces noticea
Describes a cause, reason, feeling, or quality that is real and produces noticeable effects, but is not easy to see or notice directly. For example, a hidden emotional problem that causes a person's physical pain, or the real reason behind a disagreement that nobody names out loud.
The underlying cause of Mateo's back pain was stress, not a physical injury.
underlying cause + of + noun for hidden source
Putri sensed an underlying tension in the team even though everyone was smiling.
underlying tension — atmosphere beneath the surface
The report examines the underlying reasons why so many students leave school early.
Eitan could not explain the underlying fear that kept him awake at night.
文法句型
underlying + noun (cause/reason/problem)
用法筆記
Commonly paired with nouns like cause, reason, problem, issue, tension, motive, meaning. This sense emphasises that the real cause is hidden beneath a visible or surface-level situation.
常見錯誤
2. Describes a system, structure, data set, or financial asset that acts as the sup
Describes a system, structure, data set, or financial asset that acts as the support or foundation that other things rest on. For example, the technology that powers a software application, or the assets that give a financial product its value.
The app looks simple, but the underlying technology uses a complex machine-learning model.
underlying technology — technical foundation of a system
Before buying shares in a fund, investors should examine the underlying assets.
underlying assets — financial foundation of an investment
Karim designed an underlying database that stores all the customer records securely.
The underlying structure of the building uses steel beams to support the weight.
- basic
less technical; simply describes the simplest level
- foundational
emphasises that everything else rests on this layer
- core
the central, most essential part of something
- surface-level
the visible or outward layer that people interact with directly
文法句型
underlying + noun (system/structure/data/asset)
用法筆記
Frequently used in finance and computing contexts. In finance, 'underlying asset' refers to the real asset that a derivative or fund is based on. In computing, 'underlying system' or 'underlying infrastructure' refers to the hardware or software that supports an application.
常見錯誤
3. Located in a physical layer immediately under a solid outer covering, such as ea
Located in a physical layer immediately under a solid outer covering, such as earth, stone, or water. This is the most concrete meaning of the word, describing what you would find if you dug down or looked underneath.
The construction crew discovered an underlying layer of solid clay just two metres down.
underlying layer — physical stratum beneath the surface
The underlying rock in this region is granite that formed millions of years ago.
The river eroded the topsoil and exposed the underlying bedrock.
Drilling through the sand revealed an underlying layer of limestone.
- beneath
more common as a preposition; less natural as an adjective
- subsurface
technical term used in geology and engineering
- surface
the top or outermost layer that you can see or touch
文法句型
underlying + physical noun (rock/layer/soil)
用法筆記
This is the original literal meaning of 'underlying'. It is less common in everyday speech than the figurative senses. You will most often find it in geology textbooks, construction reports, and descriptions of soil or rock layers.
4. Describing the most basic or essential principle, belief, condition, or quality
Describing the most basic or essential principle, belief, condition, or quality from which all other aspects of a situation, argument, or system come. For example, the core belief that shapes a whole set of policies, or the fundamental issue that a society must address before other problems can be solved.
Do you accept the underlying principle that every citizen deserves equal treatment under the law?
underlying principle — interrogative frame for questioning a core belief
Meera and Asher actually share the same underlying beliefs about community development.
Short-term aid helps, but we must address the underlying issues of poverty and inequality.
Many educators now challenge the underlying assumption that exams are the best measure of a student's ability.
- fundamental
very close in meaning; 'fundamental' often sounds more formal and absolute
- basic
simpler and more general; may suggest simplicity rather than hidden depth
- essential
focuses on being absolutely necessary rather than being below the surface
- superficial
concerned only with surface-level details, not the core
文法句型
underlying + noun (principle/belief/issue/assumption)
用法筆記
Distinguish from sense 1: sense 1 points to a hidden cause that produces an observable effect (e.g. stress causes pain), while sense 4 points to the most basic principle that everything else in a system follows from (e.g. fairness is the basis of law). Sense 4 is closer to 'fundamental' or 'foundational' in meaning.