The grid plan, grid street plan or gridiron plan is a type of city plan in which streets run at right angles to each other, forming a grid. In the context of the culture of Ancient Greece, the grid plan is called Hippodamian plan.

The grid plan dates from antiquity and originated in multiple cultures; some of the earliest planned cities were built using grid plans.

By 2600 BC, Mohenjo-daro and Harappa, major cities of the Indus Valley Civilization (present day Pakistan), were built with blocks divided by a grid of straight streets, running north-south and east-west. Each block was subdivided by small lanes. The cities and monasteries (e.g. Julian, Takht Bahi etc.) of "Taxila Civilization" or "Ghandhara Civilization" (in modern day Pakistan) dating back to 1st millennium BCE to the 11th century CE, also had grid-based design. Islamabad, the capital of Pakistan, since 1959, was also founded on the grid-plan of the near-by Taxila ruined city of "Sirkhap".

A workers' village at Giza, Egypt (2570-2500 BC) housed a rotating labor force and was laid out in blocks of long galleries separated by streets in a formal grid. Many pyramid-cult cities used a common orientation: a north-south axis from the royal palace and an east-west axis from the temple meeting at a central plaza where King and God merged and crossed.

Grid or The Grid may refer to:

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A plan is typically any diagram or list of steps with timing and resources, used to achieve an objective. See also strategy. It is commonly understood as a temporal set of intended actions through which one expects to achieve a goal. For spatial or planar topologic or topographic sets see map.

Plans can be formal or informal:

The most popular ways to describe plans are by their breadth, time frame, and specificity; however, these planning classifications are not independent of one another. For instance, there is a close relationship between the short- and long-term categories and the strategic and operational categories.

It is common for less formal plans to be created as abstract ideas, and remain in that form as they are maintained and put to use. More formal plans as used for business and military purposes, while initially created with and as an abstract thought, are likely to be written down, drawn up or otherwise stored in a form that is accessible to multiple people across time and space. This allows more reliable collaboration in the execution of the plan.