The 'D' of ETD: Abbr.
The 'E' in the mnemonic HOMES
The 'E' of HOMES
The 'e' of i.e.
The 'EP' of UTEP
The 'eye' in broadcasting
The 'Eyes' in a hit song by The Guess Who
The 'F' in FYI
The 'Fat' in 'Fat Tuesday'
The 'going' rates
The 'H' or 'O' of H2O
The 'I' in MIT, briefly
The 'I' of IHOP: Abbr.
The 'I' of IOC: Abbr.
The 'I' of MIT: Abbr.
The 'L' of 'SNL'
The 'M' of 'MIB'
The 'M' of MSG
The 'Me' generation?
The 'O' in OWN
The 'O' of H2O
The 'O' of NATO Abbr.:
The 'O' of NOW Abbr.:
The 'O' of TV's OWN
The 'O' of WHO: Abbr.
The 'P' of the S&P 500
The 'P' of UTEP
The 'R' of P.R.
The 'S' in 'SCUBA'
The 'S' in T.S. Eliot
The 'S' of DOS: Abbr.
The 'S' of OS: Abbr.
The 'S' of RSVP
The 'SA' of ASAP
The 'Saw' series' genre
The 'SI' of WYSIWYG
The 'sum' of Descartes
The 'sun' in 'sunny side up'
The 'T' of NWT: Abbr.
The 'T' of PTA: Abbr.
The 'U' of CPU or BTU
The 'V' of RSVP
The 'veni' of 'veni, vidi, vici'
The 'who' in a whodunit
The 'Y' in BYOB
The "'em" in "Put 'em up!"
The "00" of ".00"
The "1" in 1-9
The "1" in 1/2, e.g.
The "1" in 15, really
The "1" in a 15-1 record
The "1" of 1/4
The "1" of 10-1, say
The "10" in "10"
The "10" in "first and 10": Abbr.
The "13" in PG-13
The "16" in "3:16"
The "17" in NC-17
The "2" in the formula for water, e.g.
The "2%" of 2% milk
The "20" in "Drop and give me 20!"
The "2x" and "5" in 2x + 5, e.g.
The "3" in "6 x 3 = 18"
The "3" in "6/3"
The "35" in John 11:35
The "4" in 3/4
The "5" in "6-5," e.g.
The "5" of 5^2
The "500" in the Indy 500
The "555" in 555-1212
The "60" in "going 60": Abbr.
The "7" in a 7-10 split
The "75" of $1.75: Abbr.
The "99" in $2.99, e.g.
The "A." on many a patent
The "A" and "S" of 1-Across
The "A" in "ATCO"
The "a" in "a = lw"
The "A" in "CAT scan"
The "A" in 25-Across: Abbr.
The "A" in 59-Across
The "A" in A-Rod
The "A" in A. Philip Randolph
The "A" in A.D.
The "a" in a.m.
The "A" in A/V
The "A" in ABM
The "A" in AYCE
The "A" in B.A.
The "A" in BART
The "A" in CDA, to an Idahoan
The "A" in Chester A. Arthur
The "A" in DNA
The "A" in E. A. Poe
The "A" in E.T.A.: Abbr.
The "A" in I.R.A.: Abbr.
The "A" in IPA
The "A" in James A. Garfield
The "A" in many bus. names
The "A" in many org. names
The "A" in MFA
The "A" in MoMA
The "A" in N.B.A.: Abbr.
The "A" in N.E.A.
The "A" in NATO: Abbr.
The "A" in P.T.A.: Abbr.
The "A" in PTA: Abbr.
The "A" in RAM
The "A" in RNA
The "A" in S.A.G.
The "A" in SATB
The "A" in SEATO
The "A" in T.A. (Abbr.)
The "A" in the Tokyo studio AIC
The "A" in Thomas A. Edison
The "A" in TV's ALF
The "A" in U.A.E.
The "A" in U.A.W.
The "A" in U.S.A.: Abbr.
The "A" in USA
The "A" in USNA: Abbr.
The "A" in WASP
The "A" in YMCA: Abbr.
The "A" of 38-Across
The "A" of 52-Down
The "A" of 57-Across
The "A" of 9-Across: Abbr.
The "A" of A-K-Q-J
The "A" of A.D.
The "A" of A.D.L.
The "A" of A&E
The "A" of A&M Records
The "A" of ABM
The "A" of AIM
The "A" of AWOL
The "A" of B.A.
The "A" of BART
The "A" of C.I.A.
The "A" of C.P.A. (abbr.)
The "A" of Chester A. Arthur
The "A" of D.J.I.A.
The "A" of DNA
The "A" of E. A. Poe
The "A" of E.T.A.: Abbr.
The "A" of FAQ
The "A" of I.P.A.
The "A" of I.R.A.: Abbr.
The "A" of James A. Garfield
The "A" of M.M.A.
The "A" of MoMA
The "A" of N.A. or S.A.: Abbr.
The "A" of N.B.A.: Abbr.
The "A" of N.E.A.
The "A" of NATO: Abbr.
the "A" of NSAID
The "A" of PTA (abbr.)
The "A" of Q (Abbr.)
The "A" of SAG
The "A" of San Francisco's BART
The "A" of sports' A.F.L.
The "A" of STEAM education
The "A" of the "ABC Islands"
The "A" of Thomas A. Edison
The "A" of U.A.E.
The "A" of U.S.A.: Abbr.
The "A" of U.S.D.A.: Abbr.
The "A" of W.N.B.A.: Abbr.
The "A" of WASP
The "A" often seen in 49-Across
The "a" sound in "about"
The "a" sound in "about" or "around"
The "a" sound in "above"
The "a" sound in "afire"
The "A" that makes STEM into STEAM
The "Aeneid," e.g.
The "Aeneid," for one
The "all" in "Collect them all!"
The "Appassionata" was his 23rd piano sonata
The "B" in "BCE"
The "B" in "FBI"
The "B" in G.B.S.
The "B" in GB
The "B" in its name stands for "brush"
The "B" in KB and MB
The "B" in L.B.J.
The "B" in Roy G. Biv
The "B" in TV's former The WB network
The "B" of 11-Across
The "B" of B.S.A.
The "b" of BCE
The "B" of F.B.I.
The "B" of MB
The "B" of N.B.
The "B" of Roy G. Biv
The "Ba" of BaSO4
The "BA" of the Boston museum MOBA
The "Barry Trotter" books, et al.
The "Bel Paese," to locals
The "Big Board," on Wall St.
The "Black Paintings" and others
The "black" in black ice
The "blood" in bloodstone
The "Blue Monster," to golfers
The "Butcher of Uganda"
The "c" in a + b = c
The "C" in C-SPAN
The "C" in C.S. Lewis
The "C" in CMYK
The "c" in etc.
The "C" in N.Y.C.
The "C" in T.L.C.
The "C" in the musical instruction "D.C. al fine"
The "C" in U.P.C.
The "C" in UPC
The "C" in USMC
The "C" of C. S. Lewis
The "C" of CNN
The "C" of D.R.C.
The "C" of F.C. Barcelona
The "C" of FDIC: Abbr.
The "C" of I.C.U.
The "C" of SPCA
The "C" of TLC
The "C" of U.S.M.C.
The "cave" of "cave canem"
The "cetera" of "et cetera"
The "Claudius" in Tiberius Claudius Nero
The "common" sort is said to be not so common
The "D" in CD
The "D" in DJ
The "D" in DOT
The "D" in F.D.A.
The "D" in F.D.R.
The "D" in J.D. Salinger
The "D" in jazz's Miss D
The "D" in R&D: Abbr.
The "D" in UCSD
The "D" of "NORAD"
The "D" of C.D.
The "D" of D.E.A.
The "D" of D.J.
The "D" of FDA
The "D" of John D. Rockefeller
The "D" of LED
The "D" of PRNDL
The "da-da-da-DUM!" of Beethoven's Fifth
The "daily grind"
The "Dalai" of "Dalai Lama" is Mongolian for this
The "Dark Star" trilogy, for example
The "day" in "seize the day"