To fill the current lapse of singing competitions, here’s a new one. “The Four” (Fox, 8 p.m.) begins its brief, six-episode run with four finalists in place. Their duty is to try to keep their places. Challengers audition before a panel of Sean Combs, Meghan Trainor, DJ Khaled and label exec Charlie Walk. If they all approve, the new singer will go head-to-head against one of the four of his or her choice. Ultimately, the studio audience decides. Fergie yells quite a bit as host and as in most such contests, the lights play too big a role on the geometric set.
The sixth and final season of “Nashville” (CMT, 9 p.m.) begins on cable with Hayden Panettiere’s character facing a series of questions and self doubt.
A sixth season also starts for “Project Runway All-Stars” (Lifetime, 9 p.m.).
The 1993 siege on David Koresh’s Texas compound will mark its 25th anniversary this year, so the first documentary to note it is “Truth and Lies: Waco” (ABC, 9 p.m.).
The new 10-episode “Mega Machines” (Science, 10 p.m.) will show how things like roller coasters and cargo planes are made.
It follows the new “Building Giants” (Science, 9 p.m.) about big new structures like stadiums.
The new series “The Investigation Room” (Discovery, 10 p.m.) concentrates on what happens when suspects are called in for questioning.
“Will & Grace” (NBC, 9 p.m.) date the same man.
“Young Sheldon” (CBS, 8:30 pm.) starts going to school in Dallas.
Old Sheldon, meanwhile, is planning his wedding on “The Big Bang Theory” (CBS, 8 p.m.).
Police get a load of the staff’s social media accounts on “Superstore” (NBC, 8 p.m.).
A third season starts for “Killing Fields” (Discovery, 9 p.m.), focusing this time on the 2004 death of a woman in a farming community.
The actor Charles Boyer gets a 25-film salute Thursday nights this month on Turner Classic Movies, starting with “Love Affair” (8 p.m.), “All This, and Heaven Too” (9:45 p.m.), “Liliom” (12:30 a.m.), “Conquest” (2:45 a.m.) and “Algiers” (4:45 a.m.).
NBA action includes Golden State at Houston (TNT, 8 p.m.) and Oklahoma City at Clippers (TNT, 10:30 p.m.).
Men’s college basketball includes Tennessee-Martin at Austin Peay (CBS Sports, 7 p.m.), Houston at Wichita State (ESPN, 7 p.m.), Ohio State at Iowa (ESPNU, 7 .m.), Maryland at Michigan State (Fox Sports 1, 8 p.m.), Northern Iowa at Missouri State (CBS Sports, 9 p.m.), Arizona at Utah (ESPN, 9 p.m.), Cincinnati at Temple (ESPN2, 9 p.m.), SMU at Tulane (ESPNU, 9 p.m.), UCLA at Stanford (Fox Sports 1, 10 p.m.) and Gonzaga at Pepperdine (ESPNU, 11 p.m.).
There are more U.S. Olympic trials in speedskating (NBC Sports, 6:30 p.m.) and U.S. championships in figure skating (NBC Sports, 5 and 8:30 p.m.).
In hockey’s IIHF World Junior Championship semifinals, it’s Sweden vs. U.S. (NHL, 4 p.m.) and Canada vs. Czech Republic (NHL, 8 p.m.).
Daytime Talk
Kelly Ripa and Ryan Seacrest: Kate Hudson, Gaten Matarazzo, Gina Rodriguez. The View: Greta Van Susteren. The Talk: Jessica Chasten, Cameron Mathison. Harry Connick: Katharine McPhee, Jen Welter, Melissa Ben-Ishay (rerun). Steve Harvey: Kim Zolciak-Biermann, Kroy Biermann, Nolan Gould, Rico Rodriguez. Ellen DeGeneres: Khloe Kardashian. Wendy Williams: Fergie (rerun). The Real: Kofi Siriboe (rerun).
Late Talk
Stephen Colbert: 50 Cent, Rachel Brosnahan. Jimmy Kimmel: Kobe Bryant, Khloe Kardashian, Prophets of Rage. Jimmy Fallon: Martin Short, gina Rodriguez, Spoon (rerun). Seth Meyers: Jeff Daniels, Danielle Brooks, Daniel Caesar (rerun). James Corden: Jason Segel, Seth Rogen, Jaden Smith (rerun). Carson Daly: Katee Sackhoff, (Sandy) Alex G, Katie O’Brien, Katy Collation (rerun). Trevor Noah: Jodi Kantor. Jason Klepper: David Miliband. Conan O’Brien: JB Smoove, Whitney Cummings, Joel Kim Booster (rerun).