सर्पिल प्ररोहण सोपान in English

[ sarpil prarohan sopan ] sound:

• rotating growth step

सर्पिल: spiry helicine spiral cleavage volute colubrine
प्ररोहण सोपान: growth step growtyh step सोपान
सोपान: staircase stair grade episode rung steps stepping