A bicone is a three-dimensional shape swept by revolving an isosceles triangle around its base of unequal length, or by joining two identical right circular cones, base to base.
There are 25.4mm to one (1) inch, so there would be approximately six (6) 4mm beads per inch. If buying a 16" hank of 4mm bicone beads, you would be buying approximately 100 4mm beads.
These were found in Webster's Second International: bicone bonxie coffin confix hexoic icebox office These are found in sowpods (the Scrabble Dictionary): boffin bonxie chenix coffin coiffe confix exonic icebox office