| PPS | Second addendum to a letter ... and a hint to 18-, 34-, 44- and 62-across |
| CANINE | Word often shortened to a letter and a number |
| KNOTS | One of these begins 21, 34, 44, and 58A |
| SKIPTOWN | Run off ... or how to make the answers to 17-, 21-, 34-, 44- and 53-Across fit their clues |
| SPELLBOUND | Entranced ... or what one can do by reading the starts of 17-, 24-, 34-, 44- and 50-Across in order? |
| TEAFORTWO | We're told a letter and a number as well, a number in the 20s (3,3,3) |
| FZERO | Nintendo racing series whose name comprises a letter and a number |
| ASICS | Running shoe brand that sounds like a letter and a number |
| PPPS | Third addendum to a letter |
| CHARACTER | A letter and a card (9) |
| ABO | Blood-typing letters, and a hint to the "transfusions" in this puzzle |
| WWW | Internet letters, and a hint to this puzzle's theme |
| PUNINTENDED | Addendum to a statement such as "My violin teacher was instrumental in getting me into Juilliard" |
| ATTACHMENT | Addendum to a text |
| SOMETIMESY | Addendum to a common pentad |
| DIARYSUPPLEMENT | Addendum to a log? |
| NOTHINGPERSONAL | Dubious addendum to a snide remark |
| SOLD | Addendum to a real estate sign |
| DROPSALINE | Writes a letter and so attempts to get one out of a hole? (5,1,4) |
| REPUBLICANS | Concerning inn-keepers, 7dn, 18, 34/56, 35, 37ac,43 and 52 (11) |
