Noun
a solid bulblike enlargement of the stem of some orchids
Source: WordNetThe pseudobulb has a smooth surface with lengthwise grooves, and can have different shapes, often conical or oblong. Source: Internet
The pseudobulb of Prosthechea fragrans The base of the stem of sympodial epiphytes, or in some species essentially the entire stem, may be thickened to form a pseudobulb that contains nutrients and water for drier periods. Source: Internet