What is the different between a Rima and a Rille?

[AndyWB]

Just like the topic says - on the Moon, what is the difference between a Rima and a Rille. When is one word used and the other not? Or do they mean roughly the same thing?

[paul mc c]

I think it means the same thing,isnt Rime maybe Latin.

[John]

Yes, I think Rima or Rimae is the Latin for Rille and tends to be used to refer to a specific Rille or group of Rilles, eg: Rimae Ariadaeus.

[Bizibilder]

Yes they mean the same (crack, slit, gulley, groove or similar) Rima is the Latin and Rille the English.

Must type faster!!!!!!!!!!!!!!!!!!

GOTCHA!!  Rimae is the plural of Rima!

[ronin]

Well according to an apparent wiki type site they are simialr but not identical.

Trouble is cannot make out what the difference is especially as the site appears to imply in the first line (title) they are interchangeable.

MoonWiki

Says in the first para: The IAU defines a rima as a "fissure".

Then says in 3rd para: Rilles are definitely not "fissures".

Rilles seems to be German so I wonder if we are using words from different languages that in their native language have fractionally different meanings.

Pick the one that is used most commonly.

[John]

Many rilles seem to be collapsed crater chains from the close up photos I've seen of them.

[AndyWB]

Hmm. I wonder if John is onto it, with Rima being for a specific rille. Found this on Wikipedia describing Rima Hadley (or the Hadley Rille):

"To the west of these peaks is the sinuous Rima Hadley rille where the Fallen Astronaut memorial has been placed in memory of those astronauts who died in the advancement of space exploration. "

I looked this up 'cos I'd thought it was 'Rima Hadley', but heard someone call it 'the Hadley Rille' - it's what raised the question in the first place.