Glossary · Spelling rules and patterns
What is the floss rule?
Definition
The floss rule: when a one-syllable word ends in f, l, s or z right after a short vowel, double that letter, as in cliff, bell, miss and buzz.
The name comes from the word floss, which follows its own rule. Some teachers call it the FLSZ rule or the fizz rule. The test has three parts: one syllable, a short vowel, and f, l, s or z right after it.
The rule is reliable enough to teach early, usually just after short vowels and digraphs. Common exceptions are small words such as if, of, is, has, was, bus, gas and yes. Many of those are learned as heart words anyway.
Don't apply it when the vowel is long or a team (leaf, feel), when a consonant comes first (golf, milk), or in longer words (until). A student who doubles in those spots has overlearned the rule.
In a lesson
Dictate cliff, stuff, spell and grass. Then dictate golf. The student who writes golff needs reminding that the l must come right after the vowel.
Examples
Each word with its spelling units, one per sound.
- stuffs·t·u·ff
- spells·p·e·ll
- fizzf·i·zz
- sniffs·n·i·ff
- chillch·i·ll
Words come from our lexicon, checked against a pronouncing dictionary. Words a student sees in our assessments are left out.
Why does this matter for the record?
Rate the floss rule in spelling, not reading; reading ff or ll is easy. Note overuse, like golff or seell, as well as misses.
Rate each skill as you teach it
Needs support, Developing, Secure. The rating schedules the review and builds the report.