In linguistics, aspect is a grammatical category that expresses how an action, event, or state, denoted by a verb, extends over time. Perfective aspect is used in referring to an event conceived as bounded and unitary, without reference to any flow of time during ("I helped him").

Tense–aspect–mood (commonly abbreviated ) or tense–modality–aspect (abbreviated as ) is a group of grammatical categories that are important to understanding spoken or written content, and which are marked in different ways by different languages.Disambiguating Tense, Aspect and Modality Markers for Correcting Machine Translation Error Anil Kumar et al.

<programming> (AOP) A style of programming that attempts to abstract out features common to many parts of the code beyond simple functional modules and thereby improve the quality of software. Mechanisms for defining and composing abstractions are essential elements of programming languages. The design style supported by the abstraction mechanisms of most current languages is one of breaking a system down into parameterised components that can be called upon to perform a function. But many systems have properties that don't necessarily align with the system's functional components, such as failure handling, persistence, communication, replication, coordination, memory management, or real-time constraints, and tend to cut across groups of functional components. While they can be thought about and analysed relatively separately from the basic functionality, programming them using current component-oriented languages tends to result in these aspects being spread throughout the code. The source code becomes a tangled mess of instructions for different purposes. This "tangling" phenomenon is at the heart of much needless complexity in existing software systems. A number of researchers have begun working on approaches to this problem that allow programmers to express each of a system's aspects of concern in a separate and natural form, and then automatically combine those separate descriptions into a final executable form. These approaches have been called aspect-oriented programming. {Xerox AOP homepage (http://parc.xerox.com/csl/projects/aop/)}. AspectJ (http://AspectJ.org/). {ECOOPP'99 AOP workshop (http://wwwtrese.cs.utwente.nl/aop-ecoop99/)}. (1999-11-21)

In computing, aspect-oriented programming (AOP) is a programming paradigm that aims to increase modularity by allowing the separation of cross-cutting concerns. It does so by adding behavior to existing code (an advice) without modifying the code itself, instead separately specifying which code is modified via a "pointcut" specification, such as "log all function calls when the function's name begins with 'set.

In mathematics, any vector space V has a corresponding dual vector space (or just dual space for short) consisting of all linear forms on V, together with the vector space structure of pointwise addition and scalar multiplication by constants.

In a dual-thrust solid propellant rocket engine, the propellant mass is composed of two different types (densities) of fuel. In the case of a tandem dual-thrust motor, the fuel closest to the rocket nozzle burns fast and the fuel further into the motor's body burns slower.

In a dual-thrust solid propellant rocket engine, the propellant mass is composed of two different types (densities) of fuel. In the case of a tandem dual-thrust motor, the fuel nearest to the rocket nozzle burns fast, and the fuel further into the motor's body burns slower.

Dual wielding is the technique of using two weapons, one in each hand for training or combat. It is not a common combat practice.

In mathematics, the dual bundle is an operation on vector bundles extending the operation of duality for vector spaces.

Domestic-international dual circulation () is a strategy to reorient China's economy by prioritizing domestic consumption ("internal circulation") while remaining open to international trade and investment ("external circulation"). The first academic study on dual circulation defined it as "the domestic consumption-driven economic rebalancing to achieve sustainable economic development".