What does Length and Height and Depth Refer to on a PCI card?

A PCI card can have a length, height and depth. This diagram shows a 2D image of a full size PCI card:

2D image of a full size PCI card

The length of a full size PCI card is given as 312mm. However what are the other dimensions? Is the dimension given as 106.68 normally referred to as the height or the depth? What is the other dimension usually referred to as?

Note: We are not looking for measurements. We just want to know what PCI height usually refers to, and what the other dimension should be called.

Ethernet PCI-E Sever Card Dual SFP+ Port

We doubt the PCI specifications provide definitions of common English language words like length, breadth, width, depth or height.

Height would be the vertical dimension. Obviously which dimension of the board this refers to depends on the board's orientation with respect to the nearest or dominant source of gravity! For what it is worth we would say that 106.68 is the height of the (front edge of) the card. 

This is largely because the earliest computers with add-in cards that we encountered were Apple computers where the motherboard was horizontal and the daughter-boards were oriented vertically. If the earliest computers had motherboards oriented vertically as in popular tower-cases, we might have been conditioned to refer to that dimension of the plug-in cards as their width.

The dimension perpendicular to the plane of your drawing we would describe as width. But under other circumstances I might well use another word. In a notebook PC we might refer to it as height (for the equivalent plug-in card type).

we would not be at all surprised if different manufacturers used different triplets of terms, nor would we be surprised if their choice of terms was capricious and varied arbitrarily between marketing or technical documents and across time.

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