| Binary system |
| Brain-scan letters |
| PC linkup system |
| Alkaline ecosystems |
| Letter before gee |
| 7th letter, Greek alphabet |
| Abbr. at the bottom of a business letter |
| Archaeologist's letters |
| James Bond film, to a letter writer? |
| All, e.g., for this answer's last six letters? |
| Air delivery method? |
| Andrea Bocelli delivery |
| Organizations with Greek letters |
| Confusing statements ... and a hint to the circled letters |
| ___ system (blood classification) |
| Letter before theta |
| Four-letter-word concealer |
| Four-letter fruit pronounced in three syllables |
| Delivery notation: Abbr. |
| Feature of Melvil Dewey's book classification system |
| Diagnostic lab system |
| Attend a party uninvited ... and a literal hint to five sets of circled letters |
| Surprises unpleasantly, and a hint to each starred answer's first two + last two letters |
| Buy now, pay later" system |
| Accompaniers of cover letters: Abbr. |
| Letters from the family? |
| Estimated time of delivery |
| Adjust space between letters, in printing |
| Bounced-check letters |
| Jersey delivery? |