KEYSTONE · Day 19

Tuesday, August 11, 2026 — three word bridges.

Every neighbouring pair has to make one word. SOME → DAY → LIGHT → HOUSE works because someday, daylight and lighthouse are all words. You are given the two ends; you supply the middle. More than one bridge is often legal, and any legal bridge counts.

Warm-up · written by Claude Sonnet 4.6

BLACK?????????HOLD

4 letters, then 5 letters.

Show an answer

BIRD · HOUSE

blackbird · birdhouse · household — at least 3 different legal bridges exist for this one, so a different answer may well have counted too.

Main · written by GPT-5.5

MOON??????????PLANT

5 letters, then 5 letters.

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LIGHT · HOUSE

moonlight · lighthouse · houseplant — other legal bridges may also count.

Challenge · written by Claude Haiku 4.5

HEAD?????????LOAD

5 letters, then 4 letters.

Show an answer

COUNT · DOWN

headcount · countdown · download — other legal bridges may also count.

How day 19 worked out

Day 19 ran on Tuesday, August 11, 2026. Its three bridges were BLACK to HOLD, MOON to PLANT and HEAD to LOAD. Between them they build nine compound words, all listed at the bottom of this page. Below is the answer to each bridge and what makes it fit.

Warm-up: BLACK to HOLD

The answer is BIRD then HOUSE, which gives blackbird, birdhouse and household. The first gap is 4 letters, the second is 5.

This bridge is not unique. KEYSTONE accepts 3 different pairs here and every one of them scores: GUARD · HOUSE and OUT · HOUSE work just as well as the pair above. Ends like these sit in the crowded part of the compound-word network, which is why several routes cross them.

Main: MOON to PLANT

The answer is LIGHT then HOUSE, which gives moonlight, lighthouse and houseplant. The first gap is 5 letters, the second is 5.

Only one pair in the KEYSTONE word bank joins MOON to PLANT, so this bridge had a single accepted answer. The narrow end is usually the one to solve first.

Challenge: HEAD to LOAD

The answer is COUNT then DOWN, which gives headcount, countdown and download. The first gap is 5 letters, the second is 4.

Only one pair in the KEYSTONE word bank joins HEAD to LOAD, so this bridge had a single accepted answer. The narrow end is usually the one to solve first.

Every compound word in day 19

HOUSE, LIGHT and DOWN have a page listing every compound built on them and the other chains you can run through them.

Every one of those nine compounds turns on a hinge word doing double duty. If you want to see the whole set KEYSTONE draws from, the reference list of 141 compound word hinges gives the words that attach in front of and behind each one.

Play day 19 yourself