If you use Safari in OS X and on your iPhone or iPad, then you can manage browser tabs on one device through Safari on the other device. This is doable through the use of iCloud syncing for Safari in iOS and OS X, where you can access bookmarks, history, and other details entered on one device, in Safari on another device that is signed into the same iCloud account.
The process for doing this is quite simple: In Safari for iOS, scroll up to show the Safari toolbar, and then tap the tab manager button (the two overlapping squares) to reveal your current tabs. Now tap and drag the tabs upward and you will see a listing of your Mac’s open tabs. In this list, you can tap a tab to open it, or you can drag it to the left to reveal a “Delete” option that when used will close the tab on your Mac.
Drag the tab list item left to reveal the Delete option.
This same approach works in reverse, where in Yosemite you can open Safari, and then click the tab manager toolbar button that likewise looks like a pair of overlapping squares. If this button is missing, then you can right-click the toolbar, select “Customize,” and then drag the button to a location of your choice, or you can choose Show All Tabs in the View menu (accessible with the Shift-Command-\ hotkey).
In the Safari Tab manager, you will see the current window’s tabs as preview squares, but you will then also see the tabs of your iOS device in a list under these squares. You can select one to open it in Safari, but you can also close it by clicking the “x” that appears when you hover your mouse over the tab listing. When you close it, the tab should be closed on your iOS device.
Hovering your mouse over the tab listing will show a button to delete it.
This can be a convenient option to use, but will require you have iCloud enabled on your devices and also have iCloud’s “Safari” service checked and active. Ensure this is done in OS X’s iCloud system preferences, as well as in the General > iCloud section of your iPhone or iPad’s settings, and you should be good to go.