An extension of the concept of phrasal verb is that of phrasal noun, where a verb+particle complex is nominalized.[15] The particle may come before or after the verb. standby: We are keeping the old equipment on standby, in case of emergency. back-up: Neil can provide technical backup if you need it. onset: The match was halted by the onset of rain. input: Try to come to the meeting - we'd value your input. If the particle is in first place, then the phrasal noun is never written with a hyphen, if the particle comes second, then there is sometimes a hyphen between the two parts of the phrasal noun. The two categories have different values. Particle-verb compounds in English are of ancient development, and are common to all Germanic languages, as well as to Indo-European languages in general. Those such as onset tend to retain older uses of the particles; in Old English on/an had a wider domain, which included areas which are now covered by at and in in English. Some such compound nouns have a corresponding phrasal verb but some do not, partly because of historical developments. The modern English verb+particle complex set on exists, but it means "start to attack" (set itself means start a process). In modern English there is no exact verbal phrase equivalent to the older set on, but rather various combinations which give different nuances to the idea of starting a process, such as winter has set in, set off on a journey, set up the stand, set out on a day trip, etc. Verb-particle compounds are a more modern development in English, and focus more on the action expressed by the compound; that is to say, they are more overtly "verbal".
In the physical sciences, a particle is a small localized object to which can be ascribed several physical properties such as volume or mass.[1][2] The word is rather general in meaning, and is refined as needed by various scientific fields. Something that is composed of particles may be referred to as particulate,[3] although this term is generally used to refer to a suspension of unconnected particles, rather than a connected particle aggregation. Whether objects can be considered particles depends on the scale of the context; if an object's own size is small or negligible, or if geometrical properties and structure are irrelevant, then it can be considered a particle.[4] For example, grains of sand on a beach can be considered particles because the size of one grain of sand (~1 mm) is negligible compared to the beach, and the features of individual grains of sand are usually irrelevant to the problem at hand. However, grains of sand would not be considered particles if compared to buckyballs (~1 nm).