That's a great question! In Odoo, the standard model type for persistent business objects is 'models.Model'. Here's how you'd define a 'product.category' model: from odoo import api, fields, models class ProductCategory(models.Model): _name = 'product.category' _description = 'Product Category' _rec_name = 'name' name = fields.Char(string='Category Name', required=True) description = fields.Text(string='Description') active = fields.Boolean(string='Active', default=True) parent_id = fields.Many2one('product.category', string='Parent Category') child_ids = fields.One2many('product.category', 'parent_id', string='Child Categories')