Lifecycle is the term used by Microsoft when presenting the various dates related to the sales and support of their products. The Windows Lifecycle fact sheet provides all the relevant dates for all versions of Windows.

The lifecycle for Windows 7 was recently updated by Microsoft, making October 30, 2014 the last date on which new PCs can be sold with Windows 7. Shortly afterward, that date was removed, and it now appears as ‘To be determined.’ Someone at Microsoft apparently saw the latest sales figures for Windows, and realized that given Windows 7’s growth, stopping sales of that O/S in 2014 would significantly reduce overall revenue. Presumably a new cutoff date for OEM sales of Windows 7 is being debated internally, but I have no doubt that the October 30, 2014 date will eventually be pushed back.

Ars Technica has more about this.