ihūmbi (ama-)     5  class 5
singular: i-,iri-
plural: ama-
  
materials for building a house
igihūmbi (ibi-)     4  class 4
singular: iki-,ic-
plural: ibi-,ivy-
  
thousand
materials    (for building house) ihūmbi
(to cut trees for building, to gather building materials) guhūmbira
En-En dictionary 
thousand    igihūmbi
En-En dictionary 
construction    (~ material) ihūmbi
En-En dictionary