In the field of optics, transparency (also called pellucidity or diaphaneity) is the physical property of allowing light to pass through a material; translucency (also called translucence or translucidity) only allows light to pass through diffusely. The opposite property is opacity. Transparent materials appear clear, with the overall appearance of one color, or any combination leading up to a brilliant spectrum of every color. When light encounters a material, it can interact with it in several different ways. These interactions depend on the wavelength of the light and the nature ...

In medicine and biology, transmission is the passing of a communicable disease from an infected host individual or group to a conspecific individual or group, regardless of whether the other individual was previously infected. Sometimes transmission can specifically mean infection of a previously uninfected host. The term usually refers to the transmission of microorganisms directly from one person to another by one or more of the following means: * droplet contact – coughing or sneezing on another person * direct physical contact – touching an infected person, including sexual contact * i...

In science, engineering, and other quantitative disciplines, orders of approximation refer to formal or informal terms for how precise an approximation is, and to indicate progressively more refined approximations: in increasing order of precision, a zeroth order approximation, a first order approximation, a second order approximation, and so forth. Formally, an nth order approximation is one where the order of magnitude of the error is at most x^n, or in terms of big O notation, the error is O(x^n). In suitable circumstances, approximating a function by a Taylor polynomial of degree n y...

An order of magnitude is the class of scale or magnitude of any amount, where each class contains values of a fixed ratio to the class preceding it. In its most common usage, the amount being scaled is 10 and the scale is the (base 10) exponent being applied to this amount (therefore, to be an order of magnitude greater is to be 10 times as large). Such differences in order of magnitude can be measured on the logarithmic scale in "decades" (i.e. factors of ten). It is common among scientists and technologists to say that a parameter whose value is not accurately known, or is within a ra...