field (1): (Context: Topic of study) The study of physics is categorized into fields which group related associations between physical phenomenon. The broadest classification splits Classical Physics from Modern Physics, making a division between the focus of study prior to the decades surrounding the turn of the 18th to 19th century and the focus of study since the decades surrounding the turn of the 18th to 19th century. Classical Physics vaguely refers to Classical Mechanics, Electricity & Magnetism, Thermodynamics, and Optics. Modern Physics vaguely refers to Atomic, Nuclear, Particle, and Condensed Matter (formerly known as solid state). There is no hard-and-fast rule about which topic covers which phenomenon; however, any topic which requires the use of quantum mechanics is generally considered modern; anything else is classical. Indeed, many fields are beginning to overlap as our computational prowess allows more and more complicated models. While the majority of research physicists focus on sub-field of modern physics, there is still work being done in classical physics.
field (2): (Context: Force Field) With the observation that the gravitational interaction (for example) is able to tug on massive objects without physical contact, Sir Isaac Newton invoked the principle of action-at-a-distance. While he was not happy with "an invisible hand" reaching across the cosmos, there was no physical connection to be made. Further, there is obviously a force at work (pun intended), since a dropped object speeds up (accelerates) and thereby gains kinetic energy. Since people must do work to impart energy (it takes some effort to move objects), we need to explain where the gravitational interaction stores its energy which it gives to a dropped object as it falls. (People get their energy from the chemical reactions of digesting food.) The idea is that the fundamental interactions (not just gravity) store energy in the region between the charges. This energy storage is the interaction field. When a charge is placed in the field of another charge, it feels a force and is either attracted or repelled by that other charge.
field (3): (Context: Particle Field)
field theory, lattice: (see also above)
field theory, quantum: (see also above)
force: That which causes matter to change its velocity. Studied by many people, including Galileo, it was not until Newton formulated his three laws that the concept of force was placed on solid mathematical footing. (See Newton's Laws --- Newton used the word "action" to describe what we now call "force"; we now have a different meaning for the word action.) While forces may be due to an explicit "push" or a collision, they may also be due to the interaction between objects with some property which can in general be called charge. The latter type of force is referred to as a fundamental force or more generally as an interaction between charges.
force, fundamental: That which causes matter to change its velocity via the interaction of chargedparticles. For example, the Earth pulls on any object with mass via the gravitational interaction. However, this so-called action-at-a-distance (Newton used the word "action" to describe what we now call "force"; we now have a different meaning for the word action.) has been cause for much consternation, even for Newton. The idea of causing an acceleration without direct contact (action at a distance) eventually led to the development of field theory in which all interactions are due to the exchange of particles called gauge bosons.
frequency: How often an event occurs; esp. in the context of light, for which the frequency is the reciprocal of the amount of time it takes for a single wavelength to pass a point (i.e. the rate at which the waves pass).