transition

These are where one type of bottom material or structure changes to another, for instance, a rock pile to solid rock, or sand to gravel. There can also be transition zones, such as mud lines where a river enters a lake. Fish can often be found in transition zones.

The substitution in DNA or RNA of one purine by another purine, or of one pyrimidine by another pyrimidine. See: transversion, base substitution.

The period in which the world strategic balance would shift from offensedominance to defense-dominance.

The scenario in which you upgrade an existing Microsoft Exchange organization to Exchange Server 2007. To perform the transition, you must move data from the existing Exchange servers to new Exchange 2007 servers. For example, when upgrading from an Exchange 2000 Server or Exchange Server 2003 organization to an Exchange Server 2007 organization, you perform a transition. [Exchange 2007]

In a signal, the changing from one significant condition to another. Note: Examples of transitions are the changing from one voltage level to another in a data stream, the shifting from one phase position to another in phase-shift keying, and the translation from one frequency to another in frequency-shift keying. [From Weik '89]