Newbie Q: Is "Field Level Security" the same as "Field Accessibility"?

You can modify Field Level Security from the Field Accessibility screen, but it's not the only thing you can modify.

From Modifying Field Access Settings:

From the field accessibility grid, you can click any field access setting to change the field’s accessibility in the page layout or in field-level security. The Access Settings page then lets you modify the field access settings.

• In the Field-Level Security section of the page, specify the field's access level for the profile.

Access Level                              Enabled Settings
Users can read and edit the field.        Visible
Users can read but not edit the field.    Visible and Read-Only
Users can’t read or edit the field.       None

We recommend that you use field-level security to control users’ access to fields rather than creating multiple page layouts to control field access.

• In the Page Layout section of the page, you can:
  • Select the Remove or change editability radio button and then change the field access properties for the page layout. These changes will affect all profile and record type combinations that currently use this page layout.
  • Alternatively, you can select the Choose a different page layout radio button to assign a different page layout to the profile and record type combination.