In certain contexts, you may encounter the IRS term "foundation code". This is a two-digit number used in the IRS Business Master File to describe an exempt entity. Here are the possible codes:
| Code | Description |
| 00 | All organizations except 501(c)(3). |
| 02 | Private operating foundation exempt from paying excise taxes or investment income. |
| 03 | Private operating foundation (other). |
| 04 | Private nonoperating foundation. |
| 09 | Suspense |
| 10 | Church |
| 11 | School |
| 12 | Hospital or medical research organization. |
| 13 | Organization which operates for benefit of college or university and is owned or operated by a governmental unit. |
| 14 | Governmental unit. |
| 15 | Organization which receives a substantial part of its support from a governmental unit or the general public. |
| 16 | Organization that normally receives no more than one-third of its support from gross investment income and unrelated business income and at the same time more than one-third of its support from contributions, fees, and gross receipts related to exempt purposes. |
| 17 | Organizations operated solely for the benefit of and in conjunction with organizations described in 10 through 16 above. |
| 18 | Organization organized and operated to test for public safety. |