Letter that opens with a click
Letter that requires clicking, not licking
Letter that requires no postage
Letter that resembles the "y" of Disney's signature
Letter that rhymes with "theta"
Letter that rhymes with 34-Across and 21-Down
Letter that rhymes with its preceding and following letter
Letter that rhymes with its two successors
Letter that rhymes with three other letters
Letter that rhymes with three others
Letter that some feel should have its own day, rather than pi having Pi Day
Letter that sounds like a question
Letter that sounds like a swath of seats
Letter that sounds like an expression of relief
Letter that, surprisingly, is not the end of the Greek alphabet
Letter that's also a name
Letter that's an anagram of 111-Down
Letter that's an anagram of 16-Across
Letter that's not really at the end of the Greek alphabet
Letter that's opened with a double-click
Letter thought to resemble a skull
Letter through a filter
Letter to a Viking?
Letter to cross
Letter to Liverpudlians
Letter to Odin?
Letter to Santa
Letter to the ___
Letter to the editor that might be received immediately
Letter to the editor, often
Letter to Yanni?
letter toppers
Letter train
Letter trio
Letter two after tau
Letter two before iota
Letter two before tau
Letter upon which this puzzle's theme is built
Letter used as a density symbol
Letter used in Old English and Icelandic
Letter used to represent resistance
Letter vendor?
Letter voiced by a Greek giant?
Letter wearer: Abbr.
Letter wearers, e.g.
Letter widths
Letter with a 90-degree bend
Letter with a double curve
Letter with a double twist
Letter with a limited amount of space
Letter with a right angle
Letter with a silent letter
LETTER with cost of answer free to sender
Letter with curves
Letter with no curves
Letter with the largest section in a dictionary
letter wrapper
Letter writer, of a sort
Letter writer?
Letter writer's afterthoughts
Letter writer's aid
Letter writer's embellishment
Letter writer's signoff
Letter writing and sentence diagramming, it's said
Letter writing, for example
Letter writing, it's said
Letter writing, some say
Letter written as a straight vertical line
Letter X?
Letter Y sporter
Letter you can read without the light on
Letter you don't pronounce in "jeopardy" and "leopard"
letter Zola Author
Letter-bottom abbr.
Letter-bottom letters
Letter-box inscription
Letter-cartification words
Letter-closing word
Letter-closing words
Letter-drawing guide
Letter-ending abbr.
Letter-ending word
Letter-erasing key
Letter-extending abbr.
Letter-getter, for short
Letter-getting opportunities
Letter-handling org.
Letter-named thoroughfares in Bklyn.
Letter-opening word
Letter-perfect
Letter-perfect contest?
Letter-perfect school event
Letter-reading rituals
Letter-related
Letter-routing letters
Letter-routing number
Letter-shaped add-on
Letter-shaped annex
Letter-shaped auto feature
Letter-shaped bar
Letter-shaped beam
Letter-shaped bike lock
Letter-shaped bit of NASA equipment
Letter-shaped bolt fastener
Letter-shaped bolt holder
Letter-shaped brace
Letter-shaped bridge support
Letter-shaped building addition
Letter-shaped building beam
Letter-shaped building girders
Letter-shaped building part
Letter-shaped building support
Letter-shaped clamp
Letter-shaped construction beam
Letter-shaped construction beams
Letter-shaped construction component
Letter-shaped construction piece
Letter-shaped construction pieces
Letter-shaped construction support
Letter-shaped cross
Letter-shaped dress style
Letter-shaped extensions
Letter-shaped fastener
Letter-shaped fasteners
Letter-shaped fitting
Letter-shaped gasket
Letter-shaped gasket also known as a toric joint
Letter-shaped girder
Letter-shaped girders
Letter-shaped gripper
Letter-shaped grippers
Letter-shaped hardware
Letter-shaped hardware item
Letter-shaped hardware items
Letter-shaped iron bar
Letter-shaped lift
Letter-shaped metal fastener
Letter-shaped muscles, for short
Letter-shaped opening
Letter-shaped opening for a bolt
Letter-shaped opening in a machine shop
Letter-shaped part of a grate
Letter-shaped part of a sink
Letter-shaped pipe
Letter-shaped plumbing fitting
Letter-shaped plumbing trap
Letter-shaped shelf support
Letter-shaped shirt
Letter-shaped shirt feature
Letter-shaped shoe band
Letter-shaped shoe fastener
Letter-shaped shop devices
Letter-shaped sink fitting
Letter-shaped sink pipes
Letter-shaped skyscraper support
Letter-shaped steak
Letter-shaped steel girder
Letter-shaped structural beam
Letter-shaped structural piece
Letter-shaped structural support
Letter-shaped struts
Letter-shaped support
Letter-shaped support piece
Letter-shaped supporter
Letter-shaped supports
Letter-shaped wing
Letter-shaped wood holder
Letter-shaped woodworking vise
Letter-shaped, threaded fastener
Letter-starting word
Letter-to-Santa enclosure
Letter-to-Santa itemization
Letter-to-Santa word
Letter-turner for Pat
Letter-turner of TV
letter-type
letter-writer
Letter-writer's sign-off
Letter-writers' afterthoughts: Abbr.
Letter-writing aid
Letter-writing buddy
Letter-writing friend
Letter-writing friend from far away
Letter-writing guide
Letter-writing prisoner, perhaps
LETTER, capital
Letter, of sorts
Letter?
Letter's "To:" line: Abbr.
Letter's capital?
Letter's cross stroke
Letter's end?
Letter's first word
Letter's need
Letter's number
Letter's paper
Letter's rest period?
Letter's sign
LETTERBOX
Letterboxing or geocaching, e.g.
lettered
Lettered Bklyn. thoroughfare
Lettered fords
Lettered man's letters
LETTERED persons
Lettered piece of court evidence
Lettered sandwiches
Lettered Stratego piece
Lettered theater locations
Lettered top
Letterhead abbr.
Letterhead abbr., perhaps
Letterhead art
Letterhead design
Letterhead designs
Letterhead emblem
Letterhead feature
Letterhead feature, often
Letterhead graphic
Letterhead illustration
Letterhead illustrations
Letterhead image
Letterhead imprint
Letterhead items
Letterhead letters
Letterhead symbol
LetterHEAD, e.g.
Letterhead?: Abbr.
lettering
Lettering aid
Lettering aids
Lettering choice
Lettering device
Lettering guide
Lettering liquid
Lettering that stands out
Lettering tool
Letterless grading system
Letterless phone button
Letterless phone key
Letterless phone number
Letterman airer
Letterman competition
Letterman competitor
Letterman dental feature
Letterman employer
Letterman feature
Letterman interviewee, say
Letterman left it
Letterman letters