Concept 6 of 6
Dictionary Order: Letter by Letter
Today's big idea
Compare the first letters, and only move to the second when they tie.
A shorter word that matches all the way through comes before a longer one.
How it works
👀 What's going on?
A dictionary does not care how long a word is or what it means. It sorts on letters alone, one position at a time, and it never changes its mind.
💡 Here's the trick
Look at the four words above. Every one of them starts with S, so the first letter settles nothing. Move to the second letter and you get A, E, T and U. Those go in alphabet order, which puts SAND first, then SEA, then STAR, then SUN.
🪄 How to do it
- 1.Compare the first letters, as the words above all begin with S.
- 2.If those match, move along to the second letter and compare there instead.
- 3.Order the words by whichever letter finally told them apart.
✍️ Try it
Put CAT, COW and CUP in dictionary order. Then say which comes first, MANGO or MILK.
All three start with C, so use the second letters A, O and U. That gives CAT, COW, CUP. For the pair, both start with M, and A comes before I, so MANGO comes first.
⚠️ Watch out
You might be thinking the shorter word always comes first. Length does not matter here. CUP is shorter than CATTLE, yet CATTLE comes first, because A beats U.
🌟 Why this matters
Finding a name in a class list, a word in a dictionary or a contact in a phone all work this way. Knowing where to look beats reading every entry.
Exam tip: Underline the letter that decided each pair, so you can check your order quickly.
Watch me solve one
Quanta solves it
“Watch how I think through one of these — then you try.”
THE PROBLEM
“Which comes first in dictionary order: DESK, DISH, DASH?”
- 1
Try the first letters
All three start with D, so that settles nothing.
- 2
Move to the second letter
They give E, I and A, which sort to A, E, I.
- 3
Read off the earliest
A is earliest, and the word carrying it is DASH.
- 4
Answer ✓
DASH
Now you try one — same steps, different story 👇
See it in action
⚡ Time to play!
Find the letter that decides, then order by it.
LETTER DECIDER · ROUND 1 OF 3
Step 1 · which letter decides?
Quick check
✅ VERIFICATION
Which word comes FIRST in dictionary order: PEN, PAN, POT?
⚡ Finish the activity above first to answer.
Keep going!