Dual it means that is relative to two. It's an adjective that qualifies that which is made up of two parts.
Dual is a grammatical number that in certain languages, such as Greek, indicates two people or two things, and in Portuguese it is expressed in the word "both".
Dual is an English expression that means double, binary, which has two units. In music it's what has two beats, two bars.
Dual chip cell phone
Dual chip cell phones are cell phones that receive two chips at the same time. They work with two different numbers, from the same operator or from different operators. They are also known as "dual SIM chips". Card configuration is included in the menu, where it can be accessed at any time.
The system works with the menu stored in a reserved area on the chip itself and not in the device's memory. The feature is used by either chip, simply changing the menu.
Dual Core
Dual Core is a technology present in certain processors, which have two cores or "two brains".
Dual Core, translating into Portuguese, is literally "double core". It works with a division of tasks, it has twice the amount of memory. They are capable of processing multiple tasks. Some applications are improved and are specially designed for use on Dual Core processor.